[Xen-devel] [PATCH] x86: don't hold off NMI delivery when MCE is masked

["Jan Beulich" <JBeulich@xxxxxxxx>]

Likely through copy'n'paste, all three instances of guest MCE
processing jumped to the wrong place (where NMI processing code
correctly jumps to) when MCE-s are temporarily masked (due to one
currently being processed by the guest). A nested, unmasked NMI should
get delivered immediately, however.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

--- a/xen/arch/x86/x86_32/entry.S
+++ b/xen/arch/x86/x86_32/entry.S
@@ -214,6 +214,7 @@ test_all_events:
         jnz  process_softirqs
         testb $1,VCPU_mce_pending(%ebx)
         jnz  process_mce
+.Ltest_guest_nmi:
         testb $1,VCPU_nmi_pending(%ebx)
         jnz  process_nmi
 test_guest_events:
@@ -243,7 +244,7 @@ process_softirqs:
 /* %ebx: struct vcpu */
 process_mce:
         testb $1 << VCPU_TRAP_MCE,VCPU_async_exception_mask(%ebx)
-        jnz  test_guest_events
+        jnz  .Ltest_guest_nmi
         sti
         movb $0,VCPU_mce_pending(%ebx)
         call set_guest_machinecheck_trapbounce
--- a/xen/arch/x86/x86_64/compat/entry.S
+++ b/xen/arch/x86/x86_64/compat/entry.S
@@ -103,6 +103,7 @@ ENTRY(compat_test_all_events)
         jnz   compat_process_softirqs
         testb $1,VCPU_mce_pending(%rbx)
         jnz   compat_process_mce
+.Lcompat_test_guest_nmi:
         testb $1,VCPU_nmi_pending(%rbx)
         jnz   compat_process_nmi
 compat_test_guest_events:
@@ -133,7 +134,7 @@ compat_process_softirqs:
 /* %rbx: struct vcpu */
 compat_process_mce:
         testb $1 << VCPU_TRAP_MCE,VCPU_async_exception_mask(%rbx)
-        jnz  compat_test_guest_events
+        jnz   .Lcompat_test_guest_nmi
         sti
         movb $0,VCPU_mce_pending(%rbx)
         call set_guest_machinecheck_trapbounce
--- a/xen/arch/x86/x86_64/entry.S
+++ b/xen/arch/x86/x86_64/entry.S
@@ -192,6 +192,7 @@ test_all_events:
         jnz   process_softirqs
         testb $1,VCPU_mce_pending(%rbx)
         jnz   process_mce
+.Ltest_guest_nmi:
         testb $1,VCPU_nmi_pending(%rbx)
         jnz   process_nmi
 test_guest_events:
@@ -220,7 +221,7 @@ process_softirqs:
 /* %rbx: struct vcpu */
 process_mce:
         testb $1 << VCPU_TRAP_MCE,VCPU_async_exception_mask(%rbx)
-        jnz  test_guest_events
+        jnz  .Ltest_guest_nmi
         sti
         movb $0,VCPU_mce_pending(%rbx)
         call set_guest_machinecheck_trapbounce

Attachment: x86-masked-MCE-masking-NMI.patch
Description: Text document

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel