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[PATCH 2/4] x86/xen: use specific Xen pv interrupt entry for DF
jgross at suse
Nov 16, 2020, 7:22 AM
Post #1 of 3 (11 views)
Permalink
Xen PV guests don't use IST. For double fault interrupts switch to
the same model as NMI.

Signed-off-by: Juergen Gross <jgross@suse.com>
---
arch/x86/include/asm/idtentry.h | 3 +++
arch/x86/xen/enlighten_pv.c | 8 +++++++-
arch/x86/xen/xen-asm.S | 2 +-
3 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h
index 3505c0396fa5..b35825392547 100644
--- a/arch/x86/include/asm/idtentry.h
+++ b/arch/x86/include/asm/idtentry.h
@@ -611,6 +611,9 @@ DECLARE_IDTENTRY_RAW(X86_TRAP_DB, xenpv_exc_debug);

/* #DF */
DECLARE_IDTENTRY_DF(X86_TRAP_DF, exc_double_fault);
+#ifdef CONFIG_XEN_PV
+DECLARE_IDTENTRY_RAW_ERRORCODE(X86_TRAP_DF, xenpv_exc_double_fault);
+#endif

/* #VC */
#ifdef CONFIG_AMD_MEM_ENCRYPT
diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
index 9f5e44c1f70a..803fbcb398c4 100644
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -571,6 +571,12 @@ DEFINE_IDTENTRY_RAW(xenpv_exc_nmi)
exc_nmi(regs);
}

+DEFINE_IDTENTRY_RAW_ERRORCODE(xenpv_exc_double_fault)
+{
+ /* On Xen PV, DF doesn't use IST. The C part is the sane as native. */
+ exc_double_fault(regs, error_code);
+}
+
DEFINE_IDTENTRY_RAW(xenpv_exc_debug)
{
/*
@@ -615,7 +621,7 @@ struct trap_array_entry {

static struct trap_array_entry trap_array[] = {
TRAP_ENTRY_REDIR(exc_debug, true ),
- TRAP_ENTRY(exc_double_fault, true ),
+ TRAP_ENTRY_REDIR(exc_double_fault, true ),
#ifdef CONFIG_X86_MCE
TRAP_ENTRY_REDIR(exc_machine_check, true ),
#endif
diff --git a/arch/x86/xen/xen-asm.S b/arch/x86/xen/xen-asm.S
index bc2586730a5b..1d054c915046 100644
--- a/arch/x86/xen/xen-asm.S
+++ b/arch/x86/xen/xen-asm.S
@@ -161,7 +161,7 @@ xen_pv_trap asm_exc_overflow
xen_pv_trap asm_exc_bounds
xen_pv_trap asm_exc_invalid_op
xen_pv_trap asm_exc_device_not_available
-xen_pv_trap asm_exc_double_fault
+xen_pv_trap asm_xenpv_exc_double_fault
xen_pv_trap asm_exc_coproc_segment_overrun
xen_pv_trap asm_exc_invalid_tss
xen_pv_trap asm_exc_segment_not_present
--
2.26.2
Re: [PATCH 2/4] x86/xen: use specific Xen pv interrupt entry for DF [ In reply to ]
luto at amacapital
Nov 16, 2020, 8:12 AM
Post #2 of 3 (11 views)
Permalink
On Mon, Nov 16, 2020 at 7:23 AM Juergen Gross <jgross@suse.com> wrote:
>
> Xen PV guests don't use IST. For double fault interrupts switch to
> the same model as NMI.
>
> Signed-off-by: Juergen Gross <jgross@suse.com>
> ---
> arch/x86/include/asm/idtentry.h | 3 +++
> arch/x86/xen/enlighten_pv.c | 8 +++++++-
> arch/x86/xen/xen-asm.S | 2 +-
> 3 files changed, 11 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h
> index 3505c0396fa5..b35825392547 100644
> --- a/arch/x86/include/asm/idtentry.h
> +++ b/arch/x86/include/asm/idtentry.h
> @@ -611,6 +611,9 @@ DECLARE_IDTENTRY_RAW(X86_TRAP_DB, xenpv_exc_debug);
>
> /* #DF */
> DECLARE_IDTENTRY_DF(X86_TRAP_DF, exc_double_fault);
> +#ifdef CONFIG_XEN_PV
> +DECLARE_IDTENTRY_RAW_ERRORCODE(X86_TRAP_DF, xenpv_exc_double_fault);
> +#endif
>
> /* #VC */
> #ifdef CONFIG_AMD_MEM_ENCRYPT
> diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
> index 9f5e44c1f70a..803fbcb398c4 100644
> --- a/arch/x86/xen/enlighten_pv.c
> +++ b/arch/x86/xen/enlighten_pv.c
> @@ -571,6 +571,12 @@ DEFINE_IDTENTRY_RAW(xenpv_exc_nmi)
> exc_nmi(regs);
> }
>
> +DEFINE_IDTENTRY_RAW_ERRORCODE(xenpv_exc_double_fault)
> +{
> + /* On Xen PV, DF doesn't use IST. The C part is the sane as native. */

I would like to think that code is sane, but you probably meant "same".

> + exc_double_fault(regs, error_code);
> +}
Re: [PATCH 2/4] x86/xen: use specific Xen pv interrupt entry for DF [ In reply to ]
jgross at suse
Nov 16, 2020, 8:14 AM
Post #3 of 3 (11 views)
Permalink
On 16.11.20 17:12, Andy Lutomirski wrote:
> On Mon, Nov 16, 2020 at 7:23 AM Juergen Gross <jgross@suse.com> wrote:
>>
>> Xen PV guests don't use IST. For double fault interrupts switch to
>> the same model as NMI.
>>
>> Signed-off-by: Juergen Gross <jgross@suse.com>
>> ---
>> arch/x86/include/asm/idtentry.h | 3 +++
>> arch/x86/xen/enlighten_pv.c | 8 +++++++-
>> arch/x86/xen/xen-asm.S | 2 +-
>> 3 files changed, 11 insertions(+), 2 deletions(-)
>>
>> diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h
>> index 3505c0396fa5..b35825392547 100644
>> --- a/arch/x86/include/asm/idtentry.h
>> +++ b/arch/x86/include/asm/idtentry.h
>> @@ -611,6 +611,9 @@ DECLARE_IDTENTRY_RAW(X86_TRAP_DB, xenpv_exc_debug);
>>
>> /* #DF */
>> DECLARE_IDTENTRY_DF(X86_TRAP_DF, exc_double_fault);
>> +#ifdef CONFIG_XEN_PV
>> +DECLARE_IDTENTRY_RAW_ERRORCODE(X86_TRAP_DF, xenpv_exc_double_fault);
>> +#endif
>>
>> /* #VC */
>> #ifdef CONFIG_AMD_MEM_ENCRYPT
>> diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
>> index 9f5e44c1f70a..803fbcb398c4 100644
>> --- a/arch/x86/xen/enlighten_pv.c
>> +++ b/arch/x86/xen/enlighten_pv.c
>> @@ -571,6 +571,12 @@ DEFINE_IDTENTRY_RAW(xenpv_exc_nmi)
>> exc_nmi(regs);
>> }
>>
>> +DEFINE_IDTENTRY_RAW_ERRORCODE(xenpv_exc_double_fault)
>> +{
>> + /* On Xen PV, DF doesn't use IST. The C part is the sane as native. */
>
> I would like to think that code is sane, but you probably meant "same".

Oh, this is the result of copy and paste. Now we have two sane
functions. :-)


Juergen

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