Mailing List Archive

[xen stable-4.17] x86/vmx: introduce helper to set VMX_INTR_SHADOW_NMI
commit 27abea1ba6fa68f81b98de31cf9b9ebb594ff238
Author: Roger Pau Monné <roger.pau@citrix.com>
AuthorDate: Tue Mar 21 13:41:49 2023 +0100
Commit: Jan Beulich <jbeulich@suse.com>
CommitDate: Tue Mar 21 13:41:49 2023 +0100

x86/vmx: introduce helper to set VMX_INTR_SHADOW_NMI

Introduce a small helper to OR VMX_INTR_SHADOW_NMI in
GUEST_INTERRUPTIBILITY_INFO in order to help dealing with the NMI
unblocked by IRET case. Replace the existing usage in handling
EXIT_REASON_EXCEPTION_NMI and also add such handling to EPT violations
and page-modification log-full events.

Reported-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
master commit: d329b37d12132164c3894d0b6284be72576ef950
master date: 2022-12-19 11:23:34 +0100
---
xen/arch/x86/hvm/vmx/vmx.c | 28 +++++++++++++++++++++-------
xen/arch/x86/include/asm/hvm/vmx/vmx.h | 3 +++
2 files changed, 24 insertions(+), 7 deletions(-)

diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
index d0f0f2e429..456726e897 100644
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -3967,6 +3967,15 @@ static int vmx_handle_apic_write(void)
return vlapic_apicv_write(current, exit_qualification & 0xfff);
}

+static void undo_nmis_unblocked_by_iret(void)
+{
+ unsigned long guest_info;
+
+ __vmread(GUEST_INTERRUPTIBILITY_INFO, &guest_info);
+ __vmwrite(GUEST_INTERRUPTIBILITY_INFO,
+ guest_info | VMX_INTR_SHADOW_NMI);
+}
+
void vmx_vmexit_handler(struct cpu_user_regs *regs)
{
unsigned long exit_qualification, exit_reason, idtv_info, intr_info = 0;
@@ -4167,13 +4176,7 @@ void vmx_vmexit_handler(struct cpu_user_regs *regs)
if ( unlikely(intr_info & INTR_INFO_NMI_UNBLOCKED_BY_IRET) &&
!(idtv_info & INTR_INFO_VALID_MASK) &&
(vector != TRAP_double_fault) )
- {
- unsigned long guest_info;
-
- __vmread(GUEST_INTERRUPTIBILITY_INFO, &guest_info);
- __vmwrite(GUEST_INTERRUPTIBILITY_INFO,
- guest_info | VMX_INTR_SHADOW_NMI);
- }
+ undo_nmis_unblocked_by_iret();

perfc_incra(cause_vector, vector);

@@ -4539,6 +4542,11 @@ void vmx_vmexit_handler(struct cpu_user_regs *regs)

__vmread(GUEST_PHYSICAL_ADDRESS, &gpa);
__vmread(EXIT_QUALIFICATION, &exit_qualification);
+
+ if ( unlikely(exit_qualification & INTR_INFO_NMI_UNBLOCKED_BY_IRET) &&
+ !(idtv_info & INTR_INFO_VALID_MASK) )
+ undo_nmis_unblocked_by_iret();
+
ept_handle_violation(exit_qualification, gpa);
break;
}
@@ -4583,6 +4591,12 @@ void vmx_vmexit_handler(struct cpu_user_regs *regs)
break;

case EXIT_REASON_PML_FULL:
+ __vmread(EXIT_QUALIFICATION, &exit_qualification);
+
+ if ( unlikely(exit_qualification & INTR_INFO_NMI_UNBLOCKED_BY_IRET) &&
+ !(idtv_info & INTR_INFO_VALID_MASK) )
+ undo_nmis_unblocked_by_iret();
+
vmx_vcpu_flush_pml_buffer(v);
break;

diff --git a/xen/arch/x86/include/asm/hvm/vmx/vmx.h b/xen/arch/x86/include/asm/hvm/vmx/vmx.h
index 03995701a1..eae39365aa 100644
--- a/xen/arch/x86/include/asm/hvm/vmx/vmx.h
+++ b/xen/arch/x86/include/asm/hvm/vmx/vmx.h
@@ -225,6 +225,9 @@ static inline void pi_clear_sn(struct pi_desc *pi_desc)

/*
* Interruption-information format
+ *
+ * Note INTR_INFO_NMI_UNBLOCKED_BY_IRET is also used with Exit Qualification
+ * field for EPT violations, PML full and SPP-related event vmexits.
*/
#define INTR_INFO_VECTOR_MASK 0xff /* 7:0 */
#define INTR_INFO_INTR_TYPE_MASK 0x700 /* 10:8 */
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.17