[v2,2/3] SVM: sync VM-exit perf counters with known VM-exit reasons

Commit Message

Jan Beulich Jan. 5, 2022, 1:58 p.m. UTC

This has gone out of sync over time, resulting in NPF and XSETBV exits
incrementing the same counter. Introduce a simplistic mechanism to
hopefully keep things in better sync going forward.

Signed-off-by: Jan Beulich <[e-mail]>
---
v2: Use sentinel comments only.

Comments

Roger Pau Monne Feb. 22, 2022, 9:21 a.m. UTC | #1

On Wed, Jan 05, 2022 at 02:58:11PM +0100, Jan Beulich wrote:
> This has gone out of sync over time, resulting in NPF and XSETBV exits
> incrementing the same counter. Introduce a simplistic mechanism to
> hopefully keep things in better sync going forward.
> 
> Signed-off-by: Jan Beulich <[e-mail]>

Reviewed-by: Roger Pau Monné <[e-mail]>

Thanks, Roger.

Patch

--- a/xen/arch/x86/include/asm/hvm/svm/vmcb.h
+++ b/xen/arch/x86/include/asm/hvm/svm/vmcb.h
@@ -302,7 +302,9 @@  enum VMEXIT_EXITCODE
     VMEXIT_MWAIT_CONDITIONAL= 140, /* 0x8c */
     VMEXIT_XSETBV           = 141, /* 0x8d */
     VMEXIT_RDPRU            = 142, /* 0x8e */
+    /* Remember to also update VMEXIT_NPF_PERFC! */
     VMEXIT_NPF              = 1024, /* 0x400, nested paging fault */
+    /* Remember to also update SVM_PERF_EXIT_REASON_SIZE! */
     VMEXIT_INVALID          =  -1
 };
 
--- a/xen/arch/x86/include/asm/perfc_defn.h
+++ b/xen/arch/x86/include/asm/perfc_defn.h
@@ -11,8 +11,8 @@  PERFCOUNTER_ARRAY(exceptions,
 PERFCOUNTER_ARRAY(vmexits,              "vmexits", VMX_PERF_EXIT_REASON_SIZE)
 PERFCOUNTER_ARRAY(cause_vector,         "cause vector", VMX_PERF_VECTOR_SIZE)
 
-#define VMEXIT_NPF_PERFC 141
-#define SVM_PERF_EXIT_REASON_SIZE (1+141)
+#define VMEXIT_NPF_PERFC 143
+#define SVM_PERF_EXIT_REASON_SIZE (VMEXIT_NPF_PERFC + 1)
 PERFCOUNTER_ARRAY(svmexits,             "SVMexits", SVM_PERF_EXIT_REASON_SIZE)
 
 #endif /* CONFIG_HVM */