diff options
| author | Sean Christopherson <seanjc@google.com> | 2025-11-13 14:56:14 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2026-01-19 13:11:51 +0100 |
| commit | 2a2e0f19a7340ae05fc80f28cc28c648a296213d (patch) | |
| tree | d1ceb9fc953f1aefcfd33825eefd2af3d96d966e /arch | |
| parent | 3433c1a74139c1a17ec10d1197e955455eebd8ed (diff) | |
KVM: nSVM: Set exit_code_hi to -1 when synthesizing SVM_EXIT_ERR (failed VMRUN)
commit f402ecd7a8b6446547076f4bd24bd5d4dcc94481 upstream.
Set exit_code_hi to -1u as a temporary band-aid to fix a long-standing
(effectively since KVM's inception) bug where KVM treats the exit code as
a 32-bit value, when in reality it's a 64-bit value. Per the APM, offset
0x70 is a single 64-bit value:
070h 63:0 EXITCODE
And a sane reading of the error values defined in "Table C-1. SVM Intercept
Codes" is that negative values use the full 64 bits:
–1 VMEXIT_INVALID Invalid guest state in VMCB.
–2 VMEXIT_BUSYBUSY bit was set in the VMSA
–3 VMEXIT_IDLE_REQUIREDThe sibling thread is not in an idle state
-4 VMEXIT_INVALID_PMC Invalid PMC state
And that interpretation is confirmed by testing on Milan and Turin (by
setting bits in CR0[63:32] to generate VMEXIT_INVALID on VMRUN).
Furthermore, Xen has treated exitcode as a 64-bit value since HVM support
was adding in 2006 (see Xen commit d1bd157fbc ("Big merge the HVM
full-virtualisation abstractions.")).
Cc: Jim Mattson <jmattson@google.com>
Cc: Yosry Ahmed <yosry.ahmed@linux.dev>
Cc: stable@vger.kernel.org
Reviewed-by: Yosry Ahmed <yosry.ahmed@linux.dev>
Link: https://patch.msgid.link/20251113225621.1688428-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kvm/svm/nested.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c index 3e59df2ebc97..bc523302970e 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -528,7 +528,7 @@ int nested_svm_vmrun(struct vcpu_svm *svm) if (!nested_vmcb_check_save(svm, vmcb12) || !nested_vmcb_check_controls(&svm->nested.ctl)) { vmcb12->control.exit_code = SVM_EXIT_ERR; - vmcb12->control.exit_code_hi = 0; + vmcb12->control.exit_code_hi = -1u; vmcb12->control.exit_info_1 = 0; vmcb12->control.exit_info_2 = 0; goto out; @@ -587,7 +587,7 @@ out_exit_err: svm->nested.nested_run_pending = 0; svm->vmcb->control.exit_code = SVM_EXIT_ERR; - svm->vmcb->control.exit_code_hi = 0; + svm->vmcb->control.exit_code_hi = -1u; svm->vmcb->control.exit_info_1 = 0; svm->vmcb->control.exit_info_2 = 0; |