Mailing List Archive

On 05.05.2021 09:43, Michal Orzel wrote:
> --- a/xen/include/public/arch-arm.h
> +++ b/xen/include/public/arch-arm.h
> @@ -267,10 +267,10 @@ struct vcpu_guest_core_regs
>
> /* Return address and mode */
> __DECL_REG(pc64, pc32); /* ELR_EL2 */
> - uint32_t cpsr; /* SPSR_EL2 */
> + uint64_t cpsr; /* SPSR_EL2 */
>
> union {
> - uint32_t spsr_el1; /* AArch64 */
> + uint64_t spsr_el1; /* AArch64 */
> uint32_t spsr_svc; /* AArch32 */
> };

This change affects, besides domctl, also default_initialise_vcpu(),
which Arm's arch_initialise_vcpu() calls. I realize do_arm_vcpu_op()
only allows two unrelated VCPUOP_* to pass, but then I don't
understand why arch_initialise_vcpu() doesn't simply return e.g.
-EOPNOTSUPP. Hence I suspect I'm missing something.

> --- a/xen/include/public/domctl.h
> +++ b/xen/include/public/domctl.h
> @@ -38,7 +38,7 @@
> #include "hvm/save.h"
> #include "memory.h"
>
> -#define XEN_DOMCTL_INTERFACE_VERSION 0x00000013
> +#define XEN_DOMCTL_INTERFACE_VERSION 0x00000014

So this is to cover for the struct vcpu_guest_core_regs change.

> --- a/xen/include/public/vm_event.h
> +++ b/xen/include/public/vm_event.h
> @@ -266,8 +266,7 @@ struct vm_event_regs_arm {
> uint64_t ttbr1;
> uint64_t ttbcr;
> uint64_t pc;
> - uint32_t cpsr;
> - uint32_t _pad;
> + uint64_t cpsr;
> };

Then I wonder why this isn't accompanied by a similar bump of
VM_EVENT_INTERFACE_VERSION. I don't see you drop any checking /
filling of the _pad field, so existing callers may pass garbage
there, and new callers need to be prevented from looking at the
upper half when running on an older hypervisor.

Jan

Re: [PATCH v3 10/10] arm64: Change type of hsr, cpsr, spsr_el1 to uint64_t [ In reply to ]

tamas at tklengyel

May 5, 2021, 4:49 AM

Post #3 of 14 (77 views)

On Wed, May 5, 2021 at 4:00 AM Jan Beulich <jbeulich@suse.com> wrote:
>
> On 05.05.2021 09:43, Michal Orzel wrote:
> > --- a/xen/include/public/arch-arm.h
> > +++ b/xen/include/public/arch-arm.h
> > @@ -267,10 +267,10 @@ struct vcpu_guest_core_regs
> >
> > /* Return address and mode */
> > __DECL_REG(pc64, pc32); /* ELR_EL2 */
> > - uint32_t cpsr; /* SPSR_EL2 */
> > + uint64_t cpsr; /* SPSR_EL2 */
> >
> > union {
> > - uint32_t spsr_el1; /* AArch64 */
> > + uint64_t spsr_el1; /* AArch64 */
> > uint32_t spsr_svc; /* AArch32 */
> > };
>
> This change affects, besides domctl, also default_initialise_vcpu(),
> which Arm's arch_initialise_vcpu() calls. I realize do_arm_vcpu_op()
> only allows two unrelated VCPUOP_* to pass, but then I don't
> understand why arch_initialise_vcpu() doesn't simply return e.g.
> -EOPNOTSUPP. Hence I suspect I'm missing something.
>
> > --- a/xen/include/public/domctl.h
> > +++ b/xen/include/public/domctl.h
> > @@ -38,7 +38,7 @@
> > #include "hvm/save.h"
> > #include "memory.h"
> >
> > -#define XEN_DOMCTL_INTERFACE_VERSION 0x00000013
> > +#define XEN_DOMCTL_INTERFACE_VERSION 0x00000014
>
> So this is to cover for the struct vcpu_guest_core_regs change.
>
> > --- a/xen/include/public/vm_event.h
> > +++ b/xen/include/public/vm_event.h
> > @@ -266,8 +266,7 @@ struct vm_event_regs_arm {
> > uint64_t ttbr1;
> > uint64_t ttbcr;
> > uint64_t pc;
> > - uint32_t cpsr;
> > - uint32_t _pad;
> > + uint64_t cpsr;
> > };
>
> Then I wonder why this isn't accompanied by a similar bump of
> VM_EVENT_INTERFACE_VERSION. I don't see you drop any checking /
> filling of the _pad field, so existing callers may pass garbage
> there, and new callers need to be prevented from looking at the
> upper half when running on an older hypervisor.

No, there is no need to bump the vm event interface version here. They
are folding the _pad into the cpsr and the structure is always zero
initialized. There is never "garbage" in the _pad field. As such there
is no change to the structure layout or anyone using it with a header
compiled on an older version. I asked them not to bump the version for
this change.

Thanks,
Tamas

Re: [PATCH v3 10/10] arm64: Change type of hsr, cpsr, spsr_el1 to uint64_t [ In reply to ]

May 10, 2021, 11:37 PM

Post #4 of 14 (77 views)

Hi Jan,

On 05.05.2021 10:00, Jan Beulich wrote:
> On 05.05.2021 09:43, Michal Orzel wrote:
>> --- a/xen/include/public/arch-arm.h
>> +++ b/xen/include/public/arch-arm.h
>> @@ -267,10 +267,10 @@ struct vcpu_guest_core_regs
>>
>> /* Return address and mode */
>> __DECL_REG(pc64, pc32); /* ELR_EL2 */
>> - uint32_t cpsr; /* SPSR_EL2 */
>> + uint64_t cpsr; /* SPSR_EL2 */
>>
>> union {
>> - uint32_t spsr_el1; /* AArch64 */
>> + uint64_t spsr_el1; /* AArch64 */
>> uint32_t spsr_svc; /* AArch32 */
>> };
>
> This change affects, besides domctl, also default_initialise_vcpu(),
> which Arm's arch_initialise_vcpu() calls. I realize do_arm_vcpu_op()
> only allows two unrelated VCPUOP_* to pass, but then I don't
> understand why arch_initialise_vcpu() doesn't simply return e.g.
> -EOPNOTSUPP. Hence I suspect I'm missing something.
>
I agree that do_arm_vcpu_op only allows two VCPUOP* to pass and
arch_initialise_vcpu being called in case of VCPUOP_initialise
has no sense as VCPUOP_initialise is not supported on arm.
It makes sense that it should return -EOPNOTSUPP.
However do_arm_vcpu_op will not accept VCPUOP_initialise and will return
-EINVAL. So arch_initialise_vcpu for arm will not be called.
Do you think that changing this behaviour so that arch_initialise_vcpu returns
-EOPNOTSUPP should be part of this patch?

>> --- a/xen/include/public/domctl.h
>> +++ b/xen/include/public/domctl.h
>> @@ -38,7 +38,7 @@
>> #include "hvm/save.h"
>> #include "memory.h"
>>
>> -#define XEN_DOMCTL_INTERFACE_VERSION 0x00000013
>> +#define XEN_DOMCTL_INTERFACE_VERSION 0x00000014
>
> So this is to cover for the struct vcpu_guest_core_regs change.
>
>> --- a/xen/include/public/vm_event.h
>> +++ b/xen/include/public/vm_event.h
>> @@ -266,8 +266,7 @@ struct vm_event_regs_arm {
>> uint64_t ttbr1;
>> uint64_t ttbcr;
>> uint64_t pc;
>> - uint32_t cpsr;
>> - uint32_t _pad;
>> + uint64_t cpsr;
>> };
>
> Then I wonder why this isn't accompanied by a similar bump of
> VM_EVENT_INTERFACE_VERSION. I don't see you drop any checking /
> filling of the _pad field, so existing callers may pass garbage
> there, and new callers need to be prevented from looking at the
> upper half when running on an older hypervisor.
>
> Jan
>
Cheers,
Michal

Re: [PATCH v3 10/10] arm64: Change type of hsr, cpsr, spsr_el1 to uint64_t [ In reply to ]

May 12, 2021, 10:59 AM

Post #5 of 14 (77 views)

Hi,

On 11/05/2021 07:37, Michal Orzel wrote:
> On 05.05.2021 10:00, Jan Beulich wrote:
>> On 05.05.2021 09:43, Michal Orzel wrote:
>>> --- a/xen/include/public/arch-arm.h
>>> +++ b/xen/include/public/arch-arm.h
>>> @@ -267,10 +267,10 @@ struct vcpu_guest_core_regs
>>>
>>> /* Return address and mode */
>>> __DECL_REG(pc64, pc32); /* ELR_EL2 */
>>> - uint32_t cpsr; /* SPSR_EL2 */
>>> + uint64_t cpsr; /* SPSR_EL2 */
>>>
>>> union {
>>> - uint32_t spsr_el1; /* AArch64 */
>>> + uint64_t spsr_el1; /* AArch64 */
>>> uint32_t spsr_svc; /* AArch32 */
>>> };
>>
>> This change affects, besides domctl, also default_initialise_vcpu(),
>> which Arm's arch_initialise_vcpu() calls. I realize do_arm_vcpu_op()
>> only allows two unrelated VCPUOP_* to pass, but then I don't
>> understand why arch_initialise_vcpu() doesn't simply return e.g.
>> -EOPNOTSUPP. Hence I suspect I'm missing something.

I think it is just an overlooked when reviewing the following commit:

commit 192df6f9122ddebc21d0a632c10da3453aeee1c2
Author: Roger Pau Monné <roger.pau@citrix.com>
Date: Tue Dec 15 14:12:32 2015 +0100

x86: allow HVM guests to use hypercalls to bring up vCPUs

Allow the usage of the VCPUOP_initialise, VCPUOP_up, VCPUOP_down,
VCPUOP_is_up, VCPUOP_get_physid and VCPUOP_send_nmi hypercalls from HVM
guests.

This patch introduces a new structure (vcpu_hvm_context) that
should be used
in conjuction with the VCPUOP_initialise hypercall in order to
initialize
vCPUs for HVM guests.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>

On Arm, the structure vcpu_guest_context is not exposed outside of Xen
and the tools. Interestingly vcpu_guest_core_regs is but it should only
be used within vcpu_guest_context.

So as this is not used by stable ABI, it is fine to break it.

>>
> I agree that do_arm_vcpu_op only allows two VCPUOP* to pass and
> arch_initialise_vcpu being called in case of VCPUOP_initialise
> has no sense as VCPUOP_initialise is not supported on arm.
> It makes sense that it should return -EOPNOTSUPP.
> However do_arm_vcpu_op will not accept VCPUOP_initialise and will return
> -EINVAL. So arch_initialise_vcpu for arm will not be called.
> Do you think that changing this behaviour so that arch_initialise_vcpu returns
> -EOPNOTSUPP should be part of this patch?

I think this change is unrelated. So it should be handled in a follow-up
patch.

If you are taking care of this, would you mind to also look to move
struct vcpu_guest_core_regs within the #if defined(__XEN__) ||
defined(__XEN_TOOLS__)?

I will attempt to do a proper review of this patch by the end of the week.

Cheers,

--
Julien Grall

Re: [PATCH v3 10/10] arm64: Change type of hsr, cpsr, spsr_el1 to uint64_t [ In reply to ]

andrew.cooper3 at citrix

May 12, 2021, 11:14 AM

Post #6 of 14 (77 views)

On 12/05/2021 18:59, Julien Grall wrote:
> Hi,
>
> On 11/05/2021 07:37, Michal Orzel wrote:
>> On 05.05.2021 10:00, Jan Beulich wrote:
>>> On 05.05.2021 09:43, Michal Orzel wrote:
>>>> --- a/xen/include/public/arch-arm.h
>>>> +++ b/xen/include/public/arch-arm.h
>>>> @@ -267,10 +267,10 @@ struct vcpu_guest_core_regs
>>>>       /* Return address and mode */
>>>>       __DECL_REG(pc64,         pc32);             /* ELR_EL2 */
>>>> -    uint32_t cpsr;                              /* SPSR_EL2 */
>>>> +    uint64_t cpsr;                              /* SPSR_EL2 */
>>>>       union {
>>>> -        uint32_t spsr_el1;       /* AArch64 */
>>>> +        uint64_t spsr_el1;       /* AArch64 */
>>>>           uint32_t spsr_svc;       /* AArch32 */
>>>>       };
>>>
>>> This change affects, besides domctl, also default_initialise_vcpu(),
>>> which Arm's arch_initialise_vcpu() calls. I realize do_arm_vcpu_op()
>>> only allows two unrelated VCPUOP_* to pass, but then I don't
>>> understand why arch_initialise_vcpu() doesn't simply return e.g.
>>> -EOPNOTSUPP. Hence I suspect I'm missing something.
>
> I think it is just an overlooked when reviewing the following commit:
>
> commit 192df6f9122ddebc21d0a632c10da3453aeee1c2
> Author: Roger Pau Monné <roger.pau@citrix.com>
> Date:   Tue Dec 15 14:12:32 2015 +0100
>
>     x86: allow HVM guests to use hypercalls to bring up vCPUs
>
>     Allow the usage of the VCPUOP_initialise, VCPUOP_up, VCPUOP_down,
>     VCPUOP_is_up, VCPUOP_get_physid and VCPUOP_send_nmi hypercalls
> from HVM
>     guests.
>
>     This patch introduces a new structure (vcpu_hvm_context) that
> should be used
>     in conjuction with the VCPUOP_initialise hypercall in order to
> initialize
>     vCPUs for HVM guests.
>
>     Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
>     Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
>     Reviewed-by: Jan Beulich <jbeulich@suse.com>
>     Acked-by: Ian Campbell <ian.campbell@citrix.com>
>
> On Arm, the structure vcpu_guest_context is not exposed outside of Xen
> and the tools. Interestingly vcpu_guest_core_regs is but it should
> only be used within vcpu_guest_context.
>
> So as this is not used by stable ABI, it is fine to break it.
>
>>>
>> I agree that do_arm_vcpu_op only allows two VCPUOP* to pass and
>> arch_initialise_vcpu being called in case of VCPUOP_initialise
>> has no sense as VCPUOP_initialise is not supported on arm.
>> It makes sense that it should return -EOPNOTSUPP.
>> However do_arm_vcpu_op will not accept VCPUOP_initialise and will return
>> -EINVAL. So arch_initialise_vcpu for arm will not be called.
>> Do you think that changing this behaviour so that
>> arch_initialise_vcpu returns
>> -EOPNOTSUPP should be part of this patch?
>
> I think this change is unrelated. So it should be handled in a
> follow-up patch.
>
> If you are taking care of this, would you mind to also look to move
> struct vcpu_guest_core_regs within the #if defined(__XEN__) ||
> defined(__XEN_TOOLS__)?

+1. Fairly sure this is the conclusion of a discussion a year or so
back where I noted the same peculiarity, and tried to untangle the mess
which is the common vs arch specific code. (which is still outstanding,
and I don't immediately recall why.)

~Andrew

Re: [PATCH v3 10/10] arm64: Change type of hsr, cpsr, spsr_el1 to uint64_t [ In reply to ]

jbeulich at suse

May 17, 2021, 12:01 AM

Post #7 of 14 (77 views)

On 12.05.2021 19:59, Julien Grall wrote:
> Hi,
>
> On 11/05/2021 07:37, Michal Orzel wrote:
>> On 05.05.2021 10:00, Jan Beulich wrote:
>>> On 05.05.2021 09:43, Michal Orzel wrote:
>>>> --- a/xen/include/public/arch-arm.h
>>>> +++ b/xen/include/public/arch-arm.h
>>>> @@ -267,10 +267,10 @@ struct vcpu_guest_core_regs
>>>>
>>>> /* Return address and mode */
>>>> __DECL_REG(pc64, pc32); /* ELR_EL2 */
>>>> - uint32_t cpsr; /* SPSR_EL2 */
>>>> + uint64_t cpsr; /* SPSR_EL2 */
>>>>
>>>> union {
>>>> - uint32_t spsr_el1; /* AArch64 */
>>>> + uint64_t spsr_el1; /* AArch64 */
>>>> uint32_t spsr_svc; /* AArch32 */
>>>> };
>>>
>>> This change affects, besides domctl, also default_initialise_vcpu(),
>>> which Arm's arch_initialise_vcpu() calls. I realize do_arm_vcpu_op()
>>> only allows two unrelated VCPUOP_* to pass, but then I don't
>>> understand why arch_initialise_vcpu() doesn't simply return e.g.
>>> -EOPNOTSUPP. Hence I suspect I'm missing something.
>
> I think it is just an overlooked when reviewing the following commit:
>
> commit 192df6f9122ddebc21d0a632c10da3453aeee1c2
> Author: Roger Pau Monné <roger.pau@citrix.com>
> Date: Tue Dec 15 14:12:32 2015 +0100
>
> x86: allow HVM guests to use hypercalls to bring up vCPUs
>
> Allow the usage of the VCPUOP_initialise, VCPUOP_up, VCPUOP_down,
> VCPUOP_is_up, VCPUOP_get_physid and VCPUOP_send_nmi hypercalls from HVM
> guests.
>
> This patch introduces a new structure (vcpu_hvm_context) that
> should be used
> in conjuction with the VCPUOP_initialise hypercall in order to
> initialize
> vCPUs for HVM guests.
>
> Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
> Reviewed-by: Jan Beulich <jbeulich@suse.com>
> Acked-by: Ian Campbell <ian.campbell@citrix.com>
>
> On Arm, the structure vcpu_guest_context is not exposed outside of Xen
> and the tools. Interestingly vcpu_guest_core_regs is but it should only
> be used within vcpu_guest_context.
>
> So as this is not used by stable ABI, it is fine to break it.
>
>>>
>> I agree that do_arm_vcpu_op only allows two VCPUOP* to pass and
>> arch_initialise_vcpu being called in case of VCPUOP_initialise
>> has no sense as VCPUOP_initialise is not supported on arm.
>> It makes sense that it should return -EOPNOTSUPP.
>> However do_arm_vcpu_op will not accept VCPUOP_initialise and will return
>> -EINVAL. So arch_initialise_vcpu for arm will not be called.
>> Do you think that changing this behaviour so that arch_initialise_vcpu returns
>> -EOPNOTSUPP should be part of this patch?
>
> I think this change is unrelated. So it should be handled in a follow-up
> patch.

My only difference in viewing this is that I'd say the adjustment
would better be a prereq patch to this one, such that the one here
ends up being more obviously correct. Also, if the function is
indeed not meant to be reachable, besides making it return
-EOPNOTSUPP (or alike) it should probably also have
ASSERT_UNREACHABLE() added.

Jan

> If you are taking care of this, would you mind to also look to move
> struct vcpu_guest_core_regs within the #if defined(__XEN__) ||
> defined(__XEN_TOOLS__)?
>
> I will attempt to do a proper review of this patch by the end of the week.
>
> Cheers,
>

Re: [PATCH v3 10/10] arm64: Change type of hsr, cpsr, spsr_el1 to uint64_t [ In reply to ]

May 17, 2021, 9:03 AM

Post #8 of 14 (77 views)

Hi Jan,

On 17/05/2021 08:01, Jan Beulich wrote:
> On 12.05.2021 19:59, Julien Grall wrote:
>> Hi,
>>
>> On 11/05/2021 07:37, Michal Orzel wrote:
>>> On 05.05.2021 10:00, Jan Beulich wrote:
>>>> On 05.05.2021 09:43, Michal Orzel wrote:
>>>>> --- a/xen/include/public/arch-arm.h
>>>>> +++ b/xen/include/public/arch-arm.h
>>>>> @@ -267,10 +267,10 @@ struct vcpu_guest_core_regs
>>>>>
>>>>> /* Return address and mode */
>>>>> __DECL_REG(pc64, pc32); /* ELR_EL2 */
>>>>> - uint32_t cpsr; /* SPSR_EL2 */
>>>>> + uint64_t cpsr; /* SPSR_EL2 */
>>>>>
>>>>> union {
>>>>> - uint32_t spsr_el1; /* AArch64 */
>>>>> + uint64_t spsr_el1; /* AArch64 */
>>>>> uint32_t spsr_svc; /* AArch32 */
>>>>> };
>>>>
>>>> This change affects, besides domctl, also default_initialise_vcpu(),
>>>> which Arm's arch_initialise_vcpu() calls. I realize do_arm_vcpu_op()
>>>> only allows two unrelated VCPUOP_* to pass, but then I don't
>>>> understand why arch_initialise_vcpu() doesn't simply return e.g.
>>>> -EOPNOTSUPP. Hence I suspect I'm missing something.
>>
>> I think it is just an overlooked when reviewing the following commit:
>>
>> commit 192df6f9122ddebc21d0a632c10da3453aeee1c2
>> Author: Roger Pau Monné <roger.pau@citrix.com>
>> Date: Tue Dec 15 14:12:32 2015 +0100
>>
>> x86: allow HVM guests to use hypercalls to bring up vCPUs
>>
>> Allow the usage of the VCPUOP_initialise, VCPUOP_up, VCPUOP_down,
>> VCPUOP_is_up, VCPUOP_get_physid and VCPUOP_send_nmi hypercalls from HVM
>> guests.
>>
>> This patch introduces a new structure (vcpu_hvm_context) that
>> should be used
>> in conjuction with the VCPUOP_initialise hypercall in order to
>> initialize
>> vCPUs for HVM guests.
>>
>> Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
>> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
>> Reviewed-by: Jan Beulich <jbeulich@suse.com>
>> Acked-by: Ian Campbell <ian.campbell@citrix.com>
>>
>> On Arm, the structure vcpu_guest_context is not exposed outside of Xen
>> and the tools. Interestingly vcpu_guest_core_regs is but it should only
>> be used within vcpu_guest_context.
>>
>> So as this is not used by stable ABI, it is fine to break it.
>>
>>>>
>>> I agree that do_arm_vcpu_op only allows two VCPUOP* to pass and
>>> arch_initialise_vcpu being called in case of VCPUOP_initialise
>>> has no sense as VCPUOP_initialise is not supported on arm.
>>> It makes sense that it should return -EOPNOTSUPP.
>>> However do_arm_vcpu_op will not accept VCPUOP_initialise and will return
>>> -EINVAL. So arch_initialise_vcpu for arm will not be called.
>>> Do you think that changing this behaviour so that arch_initialise_vcpu returns
>>> -EOPNOTSUPP should be part of this patch?
>>
>> I think this change is unrelated. So it should be handled in a follow-up
>> patch.
>
> My only difference in viewing this is that I'd say the adjustment
> would better be a prereq patch to this one, such that the one here
> ends up being more obviously correct.

The function is already not reachable so I felt it was unfair to require
the clean-up for merging this code.

> Also, if the function is
> indeed not meant to be reachable, besides making it return
> -EOPNOTSUPP (or alike) it should probably also have
> ASSERT_UNREACHABLE() added.

+1 on the idea.

Cheers,

--
Julien Grall

Re: [PATCH v3 10/10] arm64: Change type of hsr, cpsr, spsr_el1 to uint64_t [ In reply to ]

May 20, 2021, 11:33 PM

Post #9 of 14 (77 views)

Hi guys,

On 17.05.2021 18:03, Julien Grall wrote:
> Hi Jan,
>
> On 17/05/2021 08:01, Jan Beulich wrote:
>> On 12.05.2021 19:59, Julien Grall wrote:
>>> Hi,
>>>
>>> On 11/05/2021 07:37, Michal Orzel wrote:
>>>> On 05.05.2021 10:00, Jan Beulich wrote:
>>>>> On 05.05.2021 09:43, Michal Orzel wrote:
>>>>>> --- a/xen/include/public/arch-arm.h
>>>>>> +++ b/xen/include/public/arch-arm.h
>>>>>> @@ -267,10 +267,10 @@ struct vcpu_guest_core_regs
>>>>>>           /* Return address and mode */
>>>>>>        __DECL_REG(pc64,         pc32);             /* ELR_EL2 */
>>>>>> -    uint32_t cpsr;                              /* SPSR_EL2 */
>>>>>> +    uint64_t cpsr;                              /* SPSR_EL2 */
>>>>>>           union {
>>>>>> -        uint32_t spsr_el1;       /* AArch64 */
>>>>>> +        uint64_t spsr_el1;       /* AArch64 */
>>>>>>            uint32_t spsr_svc;       /* AArch32 */
>>>>>>        };
>>>>>
>>>>> This change affects, besides domctl, also default_initialise_vcpu(),
>>>>> which Arm's arch_initialise_vcpu() calls. I realize do_arm_vcpu_op()
>>>>> only allows two unrelated VCPUOP_* to pass, but then I don't
>>>>> understand why arch_initialise_vcpu() doesn't simply return e.g.
>>>>> -EOPNOTSUPP. Hence I suspect I'm missing something.
>>>
>>> I think it is just an overlooked when reviewing the following commit:
>>>
>>> commit 192df6f9122ddebc21d0a632c10da3453aeee1c2
>>> Author: Roger Pau Monné <roger.pau@citrix.com>
>>> Date:   Tue Dec 15 14:12:32 2015 +0100
>>>
>>>       x86: allow HVM guests to use hypercalls to bring up vCPUs
>>>
>>>       Allow the usage of the VCPUOP_initialise, VCPUOP_up, VCPUOP_down,
>>>       VCPUOP_is_up, VCPUOP_get_physid and VCPUOP_send_nmi hypercalls from HVM
>>>       guests.
>>>
>>>       This patch introduces a new structure (vcpu_hvm_context) that
>>> should be used
>>>       in conjuction with the VCPUOP_initialise hypercall in order to
>>> initialize
>>>       vCPUs for HVM guests.
>>>
>>>       Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
>>>       Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
>>>       Reviewed-by: Jan Beulich <jbeulich@suse.com>
>>>       Acked-by: Ian Campbell <ian.campbell@citrix.com>
>>>
>>> On Arm, the structure vcpu_guest_context is not exposed outside of Xen
>>> and the tools. Interestingly vcpu_guest_core_regs is but it should only
>>> be used within vcpu_guest_context.
>>>
>>> So as this is not used by stable ABI, it is fine to break it.
>>>
>>>>>
>>>> I agree that do_arm_vcpu_op only allows two VCPUOP* to pass and
>>>> arch_initialise_vcpu being called in case of VCPUOP_initialise
>>>> has no sense as VCPUOP_initialise is not supported on arm.
>>>> It makes sense that it should return -EOPNOTSUPP.
>>>> However do_arm_vcpu_op will not accept VCPUOP_initialise and will return
>>>> -EINVAL. So arch_initialise_vcpu for arm will not be called.
>>>> Do you think that changing this behaviour so that arch_initialise_vcpu returns
>>>> -EOPNOTSUPP should be part of this patch?
>>>
>>> I think this change is unrelated. So it should be handled in a follow-up
>>> patch.
>>
>> My only difference in viewing this is that I'd say the adjustment
>> would better be a prereq patch to this one, such that the one here
>> ends up being more obviously correct.
>
> The function is already not reachable so I felt it was unfair to require the clean-up for merging this code.
>
>> Also, if the function is
>> indeed not meant to be reachable, besides making it return
>> -EOPNOTSUPP (or alike) it should probably also have
>> ASSERT_UNREACHABLE() added.
>
> +1 on the idea.
>
> Cheers,
>
FWICS, all the discussion is about creating the next patch fixing the VCPUOP_initialise function.
Is there anything left to do in this patch or are you going to ack it?

Cheers,
Michal

Re: [PATCH v3 10/10] arm64: Change type of hsr, cpsr, spsr_el1 to uint64_t [ In reply to ]

jbeulich at suse

May 21, 2021, 12:07 AM

Post #10 of 14 (77 views)

On 21.05.2021 08:33, Michal Orzel wrote:
> On 17.05.2021 18:03, Julien Grall wrote:
>> On 17/05/2021 08:01, Jan Beulich wrote:
>>> On 12.05.2021 19:59, Julien Grall wrote:
>>>> Hi,
>>>>
>>>> On 11/05/2021 07:37, Michal Orzel wrote:
>>>>> On 05.05.2021 10:00, Jan Beulich wrote:
>>>>>> On 05.05.2021 09:43, Michal Orzel wrote:
>>>>>>> --- a/xen/include/public/arch-arm.h
>>>>>>> +++ b/xen/include/public/arch-arm.h
>>>>>>> @@ -267,10 +267,10 @@ struct vcpu_guest_core_regs
>>>>>>>           /* Return address and mode */
>>>>>>>        __DECL_REG(pc64,         pc32);             /* ELR_EL2 */
>>>>>>> -    uint32_t cpsr;                              /* SPSR_EL2 */
>>>>>>> +    uint64_t cpsr;                              /* SPSR_EL2 */
>>>>>>>           union {
>>>>>>> -        uint32_t spsr_el1;       /* AArch64 */
>>>>>>> +        uint64_t spsr_el1;       /* AArch64 */
>>>>>>>            uint32_t spsr_svc;       /* AArch32 */
>>>>>>>        };
>>>>>>
>>>>>> This change affects, besides domctl, also default_initialise_vcpu(),
>>>>>> which Arm's arch_initialise_vcpu() calls. I realize do_arm_vcpu_op()
>>>>>> only allows two unrelated VCPUOP_* to pass, but then I don't
>>>>>> understand why arch_initialise_vcpu() doesn't simply return e.g.
>>>>>> -EOPNOTSUPP. Hence I suspect I'm missing something.
>>>>
>>>> I think it is just an overlooked when reviewing the following commit:
>>>>
>>>> commit 192df6f9122ddebc21d0a632c10da3453aeee1c2
>>>> Author: Roger Pau Monné <roger.pau@citrix.com>
>>>> Date:   Tue Dec 15 14:12:32 2015 +0100
>>>>
>>>>       x86: allow HVM guests to use hypercalls to bring up vCPUs
>>>>
>>>>       Allow the usage of the VCPUOP_initialise, VCPUOP_up, VCPUOP_down,
>>>>       VCPUOP_is_up, VCPUOP_get_physid and VCPUOP_send_nmi hypercalls from HVM
>>>>       guests.
>>>>
>>>>       This patch introduces a new structure (vcpu_hvm_context) that
>>>> should be used
>>>>       in conjuction with the VCPUOP_initialise hypercall in order to
>>>> initialize
>>>>       vCPUs for HVM guests.
>>>>
>>>>       Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
>>>>       Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
>>>>       Reviewed-by: Jan Beulich <jbeulich@suse.com>
>>>>       Acked-by: Ian Campbell <ian.campbell@citrix.com>
>>>>
>>>> On Arm, the structure vcpu_guest_context is not exposed outside of Xen
>>>> and the tools. Interestingly vcpu_guest_core_regs is but it should only
>>>> be used within vcpu_guest_context.
>>>>
>>>> So as this is not used by stable ABI, it is fine to break it.
>>>>
>>>>>>
>>>>> I agree that do_arm_vcpu_op only allows two VCPUOP* to pass and
>>>>> arch_initialise_vcpu being called in case of VCPUOP_initialise
>>>>> has no sense as VCPUOP_initialise is not supported on arm.
>>>>> It makes sense that it should return -EOPNOTSUPP.
>>>>> However do_arm_vcpu_op will not accept VCPUOP_initialise and will return
>>>>> -EINVAL. So arch_initialise_vcpu for arm will not be called.
>>>>> Do you think that changing this behaviour so that arch_initialise_vcpu returns
>>>>> -EOPNOTSUPP should be part of this patch?
>>>>
>>>> I think this change is unrelated. So it should be handled in a follow-up
>>>> patch.
>>>
>>> My only difference in viewing this is that I'd say the adjustment
>>> would better be a prereq patch to this one, such that the one here
>>> ends up being more obviously correct.
>>
>> The function is already not reachable so I felt it was unfair to require the clean-up for merging this code.
>>
>>> Also, if the function is
>>> indeed not meant to be reachable, besides making it return
>>> -EOPNOTSUPP (or alike) it should probably also have
>>> ASSERT_UNREACHABLE() added.
>>
>> +1 on the idea.
>>
>> Cheers,
>>
> FWICS, all the discussion is about creating the next patch fixing the VCPUOP_initialise function.
> Is there anything left to do in this patch or are you going to ack it?

Afaic I'd find it quite helpful if that other patch was a prereq to this
one, making more obvious that the change here is not going to break
anything. But it's Arm stuff, so Arm folks get the final say anyway.

Jan

Re: [PATCH v3 10/10] arm64: Change type of hsr, cpsr, spsr_el1 to uint64_t [ In reply to ]

Jun 7, 2021, 6:16 AM

Post #11 of 14 (77 views)

On 21.05.2021 09:07, Jan Beulich wrote:
> On 21.05.2021 08:33, Michal Orzel wrote:
>> On 17.05.2021 18:03, Julien Grall wrote:
>>> On 17/05/2021 08:01, Jan Beulich wrote:
>>>> On 12.05.2021 19:59, Julien Grall wrote:
>>>>> Hi,
>>>>>
>>>>> On 11/05/2021 07:37, Michal Orzel wrote:
>>>>>> On 05.05.2021 10:00, Jan Beulich wrote:
>>>>>>> On 05.05.2021 09:43, Michal Orzel wrote:
>>>>>>>> --- a/xen/include/public/arch-arm.h
>>>>>>>> +++ b/xen/include/public/arch-arm.h
>>>>>>>> @@ -267,10 +267,10 @@ struct vcpu_guest_core_regs
>>>>>>>>           /* Return address and mode */
>>>>>>>>        __DECL_REG(pc64,         pc32);             /* ELR_EL2 */
>>>>>>>> -    uint32_t cpsr;                              /* SPSR_EL2 */
>>>>>>>> +    uint64_t cpsr;                              /* SPSR_EL2 */
>>>>>>>>           union {
>>>>>>>> -        uint32_t spsr_el1;       /* AArch64 */
>>>>>>>> +        uint64_t spsr_el1;       /* AArch64 */
>>>>>>>>            uint32_t spsr_svc;       /* AArch32 */
>>>>>>>>        };
>>>>>>>
>>>>>>> This change affects, besides domctl, also default_initialise_vcpu(),
>>>>>>> which Arm's arch_initialise_vcpu() calls. I realize do_arm_vcpu_op()
>>>>>>> only allows two unrelated VCPUOP_* to pass, but then I don't
>>>>>>> understand why arch_initialise_vcpu() doesn't simply return e.g.
>>>>>>> -EOPNOTSUPP. Hence I suspect I'm missing something.
>>>>>
>>>>> I think it is just an overlooked when reviewing the following commit:
>>>>>
>>>>> commit 192df6f9122ddebc21d0a632c10da3453aeee1c2
>>>>> Author: Roger Pau Monné <roger.pau@citrix.com>
>>>>> Date:   Tue Dec 15 14:12:32 2015 +0100
>>>>>
>>>>>       x86: allow HVM guests to use hypercalls to bring up vCPUs
>>>>>
>>>>>       Allow the usage of the VCPUOP_initialise, VCPUOP_up, VCPUOP_down,
>>>>>       VCPUOP_is_up, VCPUOP_get_physid and VCPUOP_send_nmi hypercalls from HVM
>>>>>       guests.
>>>>>
>>>>>       This patch introduces a new structure (vcpu_hvm_context) that
>>>>> should be used
>>>>>       in conjuction with the VCPUOP_initialise hypercall in order to
>>>>> initialize
>>>>>       vCPUs for HVM guests.
>>>>>
>>>>>       Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
>>>>>       Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
>>>>>       Reviewed-by: Jan Beulich <jbeulich@suse.com>
>>>>>       Acked-by: Ian Campbell <ian.campbell@citrix.com>
>>>>>
>>>>> On Arm, the structure vcpu_guest_context is not exposed outside of Xen
>>>>> and the tools. Interestingly vcpu_guest_core_regs is but it should only
>>>>> be used within vcpu_guest_context.
>>>>>
>>>>> So as this is not used by stable ABI, it is fine to break it.
>>>>>
>>>>>>>
>>>>>> I agree that do_arm_vcpu_op only allows two VCPUOP* to pass and
>>>>>> arch_initialise_vcpu being called in case of VCPUOP_initialise
>>>>>> has no sense as VCPUOP_initialise is not supported on arm.
>>>>>> It makes sense that it should return -EOPNOTSUPP.
>>>>>> However do_arm_vcpu_op will not accept VCPUOP_initialise and will return
>>>>>> -EINVAL. So arch_initialise_vcpu for arm will not be called.
>>>>>> Do you think that changing this behaviour so that arch_initialise_vcpu returns
>>>>>> -EOPNOTSUPP should be part of this patch?
>>>>>
>>>>> I think this change is unrelated. So it should be handled in a follow-up
>>>>> patch.
>>>>
>>>> My only difference in viewing this is that I'd say the adjustment
>>>> would better be a prereq patch to this one, such that the one here
>>>> ends up being more obviously correct.
>>>
>>> The function is already not reachable so I felt it was unfair to require the clean-up for merging this code.
>>>
>>>> Also, if the function is
>>>> indeed not meant to be reachable, besides making it return
>>>> -EOPNOTSUPP (or alike) it should probably also have
>>>> ASSERT_UNREACHABLE() added.
>>>
>>> +1 on the idea.
>>>
>>> Cheers,
>>>
>> FWICS, all the discussion is about creating the next patch fixing the VCPUOP_initialise function.
>> Is there anything left to do in this patch or are you going to ack it?
>
> Afaic I'd find it quite helpful if that other patch was a prereq to this
> one, making more obvious that the change here is not going to break
> anything. But it's Arm stuff, so Arm folks get the final say anyway.
This change is not going to break anything as the new patch is going to mainly add ASSERT_UNREACHABLE into VCPUOP_initialise which means it'll be a clean-up patch.
Also the problem was not introduced by this patch so I think it should be merged.
>
> Jan
>

So what is the final say from Arm folks :) ?

Re: [PATCH v3 10/10] arm64: Change type of hsr, cpsr, spsr_el1 to uint64_t [ In reply to ]

Jun 7, 2021, 6:31 AM

Post #12 of 14 (77 views)

Hi,

On 05/05/2021 08:43, Michal Orzel wrote:
> AArch64 registers are 64bit whereas AArch32 registers
> are 32bit or 64bit. MSR/MRS are expecting 64bit values thus
> we should get rid of helpers READ/WRITE_SYSREG32
> in favour of using READ/WRITE_SYSREG.
> We should also use register_t type when reading sysregs
> which can correspond to uint64_t or uint32_t.
> Even though many AArch64 registers have upper 32bit reserved
> it does not mean that they can't be widen in the future.
>
> Modify type of hsr, cpsr, spsr_el1 to uint64_t.
> Previously we relied on the padding after SPSR_EL1.
> As we removed the padding, modify the union to be 64bit so we don't corrupt SPSR_FIQ.
> No need to modify the assembly code becuase the accesses were based on 64bit

s/becuase/because/

> registers as there was a 32bit padding after SPSR_EL1.
>
> Remove 32bit padding in cpu_user_regs before spsr_fiq
> as it is no longer needed due to upper union being 64bit now.
> Add 64bit padding in cpu_user_regs before spsr_el1
> because offset of spsr_el1 must be a multiple of 8.
>
> Change type of cpsr to uint64_t in the public outside interface
> "public/arch-arm.h" to allow ABI compatibility between 32bit and 64bit.
> Increment XEN_DOMCTL_INTERFACE_VERSION.
>
> Change type of cpsr to uint64_t in the public outside interface
> "public/vm_event.h" to allow ABI compatibility between 32bit and 64bit.
[...]

> diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
> index e7384381cc..c8f9773566 100644
> --- a/xen/arch/arm/traps.c
> +++ b/xen/arch/arm/traps.c
> @@ -546,7 +546,7 @@ void inject_undef64_exception(struct cpu_user_regs *regs, int instr_len)
> PSR_IRQ_MASK | PSR_DBG_MASK;
> regs->pc = handler;
>
> - WRITE_SYSREG32(esr.bits, ESR_EL1);
> + WRITE_SYSREG(esr.bits, ESR_EL1);
> }
>
> /* Inject an abort exception into a 64 bit guest */
> @@ -580,7 +580,7 @@ static void inject_abt64_exception(struct cpu_user_regs *regs,
> regs->pc = handler;
>
> WRITE_SYSREG(addr, FAR_EL1);
> - WRITE_SYSREG32(esr.bits, ESR_EL1);
> + WRITE_SYSREG(esr.bits, ESR_EL1);
> }
>
> static void inject_dabt64_exception(struct cpu_user_regs *regs,
> @@ -717,7 +717,7 @@ struct reg_ctxt {
> uint64_t vttbr_el2;
> };
>
> -static const char *mode_string(uint32_t cpsr)
> +static const char *mode_string(register_t cpsr)
> {
> uint32_t mode;
> static const char *mode_strings[] = {
> @@ -756,14 +756,16 @@ static void show_registers_32(const struct cpu_user_regs *regs,
> #ifdef CONFIG_ARM_64
> BUG_ON( ! (regs->cpsr & PSR_MODE_BIT) );
> printk("PC: %08"PRIx32"\n", regs->pc32);
> + printk("CPSR: %016"PRIx64" MODE:%s\n", regs->cpsr,
> + mode_string(regs->cpsr));
Why do you now need to duplicate this line? Can't we use PRIregister you
did everywhere else a register is printed?

> #else
> printk("PC: %08"PRIx32, regs->pc);
> if ( !guest_mode )
> printk(" %pS", _p(regs->pc));
> printk("\n");
> -#endif
> printk("CPSR: %08"PRIx32" MODE:%s\n", regs->cpsr,
> mode_string(regs->cpsr));
> +#endif

[...]

> diff --git a/xen/include/asm-arm/arm64/processor.h b/xen/include/asm-arm/arm64/processor.h
> index 81dfc5e615..0e86079cbb 100644
> --- a/xen/include/asm-arm/arm64/processor.h
> +++ b/xen/include/asm-arm/arm64/processor.h
> @@ -63,18 +63,19 @@ struct cpu_user_regs
>
> /* Return address and mode */
> __DECL_REG(pc, pc32); /* ELR_EL2 */
> - uint32_t cpsr; /* SPSR_EL2 */
> - uint32_t hsr; /* ESR_EL2 */
> + uint64_t cpsr; /* SPSR_EL2 */
> + uint64_t hsr; /* ESR_EL2 */
> +
> + /* Offset of spsr_el1 must be a multiple of 8 */

I am guessing you are saying it should be 8-byte aligned, right? If so,
the field before is a 64-bit value, therefore the offset should already
be a multiple of 8. Did I miss anything?

> + uint64_t pad0;
>
> /* Outer guest frame only from here on... */
>
> union {
> - uint32_t spsr_el1; /* AArch64 */
> + uint64_t spsr_el1; /* AArch64 */
> uint32_t spsr_svc; /* AArch32 */
> };
>
> - uint32_t pad1; /* Doubleword-align the user half of the frame */
> -
> /* AArch32 guests only */
> uint32_t spsr_fiq, spsr_irq, spsr_und, spsr_abt;
>
> diff --git a/xen/include/asm-arm/hsr.h b/xen/include/asm-arm/hsr.h
> index 29d4531f40..9b91b28c48 100644
> --- a/xen/include/asm-arm/hsr.h
> +++ b/xen/include/asm-arm/hsr.h
> @@ -16,7 +16,7 @@ enum dabt_size {
> };
>
> union hsr {
> - uint32_t bits;
> + register_t bits;
> struct {
> unsigned long iss:25; /* Instruction Specific Syndrome */
> unsigned long len:1; /* Instruction length */
> diff --git a/xen/include/public/arch-arm.h b/xen/include/public/arch-arm.h
> index 713fd65317..64a2ca30da 100644
> --- a/xen/include/public/arch-arm.h
> +++ b/xen/include/public/arch-arm.h
> @@ -267,10 +267,10 @@ struct vcpu_guest_core_regs
>
> /* Return address and mode */
> __DECL_REG(pc64, pc32); /* ELR_EL2 */
> - uint32_t cpsr; /* SPSR_EL2 */
> + uint64_t cpsr; /* SPSR_EL2 */
>
> union {
> - uint32_t spsr_el1; /* AArch64 */
> + uint64_t spsr_el1; /* AArch64 */
> uint32_t spsr_svc; /* AArch32 */
> };
>
> diff --git a/xen/include/public/domctl.h b/xen/include/public/domctl.h
> index 4dbf107785..d576bfabd6 100644
> --- a/xen/include/public/domctl.h
> +++ b/xen/include/public/domctl.h
> @@ -38,7 +38,7 @@
> #include "hvm/save.h"
> #include "memory.h"
>
> -#define XEN_DOMCTL_INTERFACE_VERSION 0x00000013
> +#define XEN_DOMCTL_INTERFACE_VERSION 0x00000014
>
> /*
> * NB. xen_domctl.domain is an IN/OUT parameter for this operation.
> diff --git a/xen/include/public/vm_event.h b/xen/include/public/vm_event.h
> index 36135ba4f1..bb003d21d0 100644
> --- a/xen/include/public/vm_event.h
> +++ b/xen/include/public/vm_event.h
> @@ -266,8 +266,7 @@ struct vm_event_regs_arm {
> uint64_t ttbr1;
> uint64_t ttbcr;
> uint64_t pc;
> - uint32_t cpsr;
> - uint32_t _pad;
> + uint64_t cpsr;
> };
>
> /*
>

--
Julien Grall

Re: [PATCH v3 10/10] arm64: Change type of hsr, cpsr, spsr_el1 to uint64_t [ In reply to ]

Jul 1, 2021, 1:19 AM

Post #13 of 14 (77 views)

Hi Julien,

On 07.06.2021 15:31, Julien Grall wrote:
> Hi,
>
> On 05/05/2021 08:43, Michal Orzel wrote:
>> AArch64 registers are 64bit whereas AArch32 registers
>> are 32bit or 64bit. MSR/MRS are expecting 64bit values thus
>> we should get rid of helpers READ/WRITE_SYSREG32
>> in favour of using READ/WRITE_SYSREG.
>> We should also use register_t type when reading sysregs
>> which can correspond to uint64_t or uint32_t.
>> Even though many AArch64 registers have upper 32bit reserved
>> it does not mean that they can't be widen in the future.
>>
>> Modify type of hsr, cpsr, spsr_el1 to uint64_t.
>> Previously we relied on the padding after SPSR_EL1.
>> As we removed the padding, modify the union to be 64bit so we don't corrupt SPSR_FIQ.
>> No need to modify the assembly code becuase the accesses were based on 64bit
>
> s/becuase/because/
>
Will do.
>> registers as there was a 32bit padding after SPSR_EL1.
>>
>> Remove 32bit padding in cpu_user_regs before spsr_fiq
>> as it is no longer needed due to upper union being 64bit now.
>> Add 64bit padding in cpu_user_regs before spsr_el1
>> because offset of spsr_el1 must be a multiple of 8.
>>
>> Change type of cpsr to uint64_t in the public outside interface
>> "public/arch-arm.h" to allow ABI compatibility between 32bit and 64bit.
>> Increment XEN_DOMCTL_INTERFACE_VERSION.
>>
>> Change type of cpsr to uint64_t in the public outside interface
>> "public/vm_event.h" to allow ABI compatibility between 32bit and 64bit.
> [...]
>
>> diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
>> index e7384381cc..c8f9773566 100644
>> --- a/xen/arch/arm/traps.c
>> +++ b/xen/arch/arm/traps.c
>> @@ -546,7 +546,7 @@ void inject_undef64_exception(struct cpu_user_regs *regs, int instr_len)
>>           PSR_IRQ_MASK | PSR_DBG_MASK;
>>       regs->pc = handler;
>> -    WRITE_SYSREG32(esr.bits, ESR_EL1);
>> +    WRITE_SYSREG(esr.bits, ESR_EL1);
>> }
>> /* Inject an abort exception into a 64 bit guest */
>> @@ -580,7 +580,7 @@ static void inject_abt64_exception(struct cpu_user_regs *regs,
>>       regs->pc = handler;
>>       WRITE_SYSREG(addr, FAR_EL1);
>> -    WRITE_SYSREG32(esr.bits, ESR_EL1);
>> +    WRITE_SYSREG(esr.bits, ESR_EL1);
>> }
>> static void inject_dabt64_exception(struct cpu_user_regs *regs,
>> @@ -717,7 +717,7 @@ struct reg_ctxt {
>>       uint64_t vttbr_el2;
>> };
>> -static const char *mode_string(uint32_t cpsr)
>> +static const char *mode_string(register_t cpsr)
>> {
>>       uint32_t mode;
>>       static const char *mode_strings[] = {
>> @@ -756,14 +756,16 @@ static void show_registers_32(const struct cpu_user_regs *regs,
>> #ifdef CONFIG_ARM_64
>>       BUG_ON( ! (regs->cpsr & PSR_MODE_BIT) );
>>       printk("PC:     %08"PRIx32"\n", regs->pc32);
>> +    printk("CPSR:   %016"PRIx64" MODE:%s\n", regs->cpsr,
>> +           mode_string(regs->cpsr));
> Why do you now need to duplicate this line? Can't we use PRIregister you did everywhere else a register is printed?
>
Indeed we do not need. It was needed at the beginning but I do not remember why. I will fix it.
>> #else
>>       printk("PC:     %08"PRIx32, regs->pc);
>>       if ( !guest_mode )
>>           printk(" %pS", _p(regs->pc));
>>       printk("\n");
>> -#endif
>>       printk("CPSR:   %08"PRIx32" MODE:%s\n", regs->cpsr,
>>              mode_string(regs->cpsr));
>> +#endif
>
> [...]
>
>> diff --git a/xen/include/asm-arm/arm64/processor.h b/xen/include/asm-arm/arm64/processor.h
>> index 81dfc5e615..0e86079cbb 100644
>> --- a/xen/include/asm-arm/arm64/processor.h
>> +++ b/xen/include/asm-arm/arm64/processor.h
>> @@ -63,18 +63,19 @@ struct cpu_user_regs
>>       /* Return address and mode */
>>       __DECL_REG(pc,           pc32);             /* ELR_EL2 */
>> -    uint32_t cpsr;                              /* SPSR_EL2 */
>> -    uint32_t hsr;                               /* ESR_EL2 */
>> +    uint64_t cpsr;                              /* SPSR_EL2 */
>> +    uint64_t hsr;                               /* ESR_EL2 */
>> +
>> +    /* Offset of spsr_el1 must be a multiple of 8 */
>
> I am guessing you are saying it should be 8-byte aligned, right? If so, the field before is a 64-bit value, therefore the offset should already be a multiple of 8. Did I miss anything?
>
Well, instead of 8 I should write 16.
We have 2 bug_on checks:
1) BUILD_BUG_ON((sizeof (struct cpu_user_regs)) & 0xf);
2) BUILD_BUG_ON((offsetof(struct cpu_user_regs, spsr_el1)) & 0xf);

Total size of cpu_user_regs without padding is 344 which does not pass the first check.
With the padding it is 352 and it passes the first check.

The offset without padding is 280 which does not pass the second check.
The offset with padding is 288 which passes the second check.

So I should write:
"/* Offset of spsr_el1 must be a multiple of 16 bytes */"

Is it ok for you?
If yes, I will push v3.
>> +    uint64_t pad0;
>>       /* Outer guest frame only from here on... */
>>       union {
>> -        uint32_t spsr_el1;       /* AArch64 */
>> +        uint64_t spsr_el1;       /* AArch64 */
>>           uint32_t spsr_svc;       /* AArch32 */
>>       };
>> -    uint32_t pad1; /* Doubleword-align the user half of the frame */
>> -
>>       /* AArch32 guests only */
>>       uint32_t spsr_fiq, spsr_irq, spsr_und, spsr_abt;
>> diff --git a/xen/include/asm-arm/hsr.h b/xen/include/asm-arm/hsr.h
>> index 29d4531f40..9b91b28c48 100644
>> --- a/xen/include/asm-arm/hsr.h
>> +++ b/xen/include/asm-arm/hsr.h
>> @@ -16,7 +16,7 @@ enum dabt_size {
>> };
>> union hsr {
>> -    uint32_t bits;
>> +    register_t bits;
>>       struct {
>>           unsigned long iss:25; /* Instruction Specific Syndrome */
>>           unsigned long len:1;   /* Instruction length */
>> diff --git a/xen/include/public/arch-arm.h b/xen/include/public/arch-arm.h
>> index 713fd65317..64a2ca30da 100644
>> --- a/xen/include/public/arch-arm.h
>> +++ b/xen/include/public/arch-arm.h
>> @@ -267,10 +267,10 @@ struct vcpu_guest_core_regs
>>       /* Return address and mode */
>>       __DECL_REG(pc64,         pc32);             /* ELR_EL2 */
>> -    uint32_t cpsr;                              /* SPSR_EL2 */
>> +    uint64_t cpsr;                              /* SPSR_EL2 */
>>       union {
>> -        uint32_t spsr_el1;       /* AArch64 */
>> +        uint64_t spsr_el1;       /* AArch64 */
>>           uint32_t spsr_svc;       /* AArch32 */
>>       };
>> diff --git a/xen/include/public/domctl.h b/xen/include/public/domctl.h
>> index 4dbf107785..d576bfabd6 100644
>> --- a/xen/include/public/domctl.h
>> +++ b/xen/include/public/domctl.h
>> @@ -38,7 +38,7 @@
>> #include "hvm/save.h"
>> #include "memory.h"
>> -#define XEN_DOMCTL_INTERFACE_VERSION 0x00000013
>> +#define XEN_DOMCTL_INTERFACE_VERSION 0x00000014
>> /*
>>    * NB. xen_domctl.domain is an IN/OUT parameter for this operation.
>> diff --git a/xen/include/public/vm_event.h b/xen/include/public/vm_event.h
>> index 36135ba4f1..bb003d21d0 100644
>> --- a/xen/include/public/vm_event.h
>> +++ b/xen/include/public/vm_event.h
>> @@ -266,8 +266,7 @@ struct vm_event_regs_arm {
>>       uint64_t ttbr1;
>>       uint64_t ttbcr;
>>       uint64_t pc;
>> -    uint32_t cpsr;
>> -    uint32_t _pad;
>> +    uint64_t cpsr;
>> };
>> /*
>>
>

Cheers,
Michal

Re: [PATCH v3 10/10] arm64: Change type of hsr, cpsr, spsr_el1 to uint64_t [ In reply to ]

Jul 3, 2021, 7:42 AM

Post #14 of 14 (77 views)