On Thu, Nov 13, 2025, Sean Christopherson wrote:
> Fix KVM's long-standing buggy handling of SVM's exit_code as a 32-bit
> value. Per the APM and Xen commit d1bd157fbc ("Big merge the HVM
> full-virtualisation abstractions.") (which is arguably more trustworthy
> than KVM), offset 0x70 is a single 64-bit value:
>
> 070h 63:0 EXITCODE
>
> Track exit_code as a single u64 to prevent reintroducing bugs where KVM
> neglects to correctly set bits 63:32.
>
> Fixes: 6aa8b732ca01 ("[PATCH] kvm: userspace interface")
> Cc: Jim Mattson <[email protected]>
> Cc: Yosry Ahmed <[email protected]>
> Signed-off-by: Sean Christopherson <[email protected]>
> ---
...
> diff --git a/arch/x86/kvm/trace.h b/arch/x86/kvm/trace.h
> index e79bc9cb7162..4c7a5cd10990 100644
> --- a/arch/x86/kvm/trace.h
> +++ b/arch/x86/kvm/trace.h
> @@ -781,7 +781,7 @@ TRACE_EVENT_KVM_EXIT(kvm_nested_vmexit);
> * Tracepoint for #VMEXIT reinjected to the guest
> */
> TRACE_EVENT(kvm_nested_vmexit_inject,
> - TP_PROTO(__u32 exit_code,
> + TP_PROTO(__u64 exit_code,
> __u64 exit_info1, __u64 exit_info2,
> __u32 exit_int_info, __u32 exit_int_info_err, __u32 isa),
> TP_ARGS(exit_code, exit_info1, exit_info2,
As pointed out by the test bot[*], the trace macro to print exit reasons needs
to use 64-bit variants to play nice with 32-bit builds.
And now I'm questioning all of my testing, because my build setup detects that
as well, _and_ the hyperv_svm_test selftest fails. *sigh*
diff --git a/arch/x86/kvm/trace.h b/arch/x86/kvm/trace.h
index 4c7a5cd10990..0fd72ce83926 100644
--- a/arch/x86/kvm/trace.h
+++ b/arch/x86/kvm/trace.h
@@ -383,10 +383,10 @@ TRACE_EVENT(kvm_apic,
#define kvm_print_exit_reason(exit_reason, isa)
\
(isa == KVM_ISA_VMX) ? \
__print_symbolic(exit_reason & 0xffff, VMX_EXIT_REASONS) : \
- __print_symbolic(exit_reason, SVM_EXIT_REASONS), \
+ __print_symbolic64(exit_reason, SVM_EXIT_REASONS), \
(isa == KVM_ISA_VMX && exit_reason & ~0xffff) ? " " : "", \
(isa == KVM_ISA_VMX) ? \
- __print_flags(exit_reason & ~0xffff, " ", VMX_EXIT_REASON_FLAGS) : ""
+ __print_flags64(exit_reason & ~0xffff, " ", VMX_EXIT_REASON_FLAGS) : ""
#define TRACE_EVENT_KVM_EXIT(name) \
TRACE_EVENT(name,
[*] https://lore.kernel.org/all/[email protected]
