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| author | Yosry Ahmed <yosry@kernel.org> | 2026-02-27 04:13:06 +0300 |
|---|---|---|
| committer | Sean Christopherson <seanjc@google.com> | 2026-03-03 02:27:27 +0300 |
| commit | e907b4e72488f1df878e7e8acf88d23e49cb3ca7 (patch) | |
| tree | 9309ab0b8e83f7811aacbe91b0f21a72f7372599 | |
| parent | 5a6b189317501169b0510f2f1256cfc0c6ca81c7 (diff) | |
| download | linux-e907b4e72488f1df878e7e8acf88d23e49cb3ca7.tar.xz | |
KVM: x86: Check for injected exceptions before queuing a debug exception
On KVM_SET_GUEST_DEBUG, if a #DB or #BP is injected with
KVM_GUESTDBG_INJECT_DB or KVM_GUESTDBG_INJECT_BP, KVM fails with -EBUSY
if there is an existing pending exception. This was introduced in
commit 4f926bf29186 ("KVM: x86: Polish exception injection via
KVM_SET_GUEST_DEBUG") to avoid a warning in kvm_queue_exception(),
presumably to avoid overriding a pending exception.
This added another (arguably nice) property, if there's a pending
exception, KVM_SET_GUEST_DEBUG cannot cause a #DF or triple fault.
However, if an exception is injected, KVM_SET_GUEST_DEBUG will cause
a #DF or triple fault in the guest, as kvm_multiple_exception() combines
them.
Check for both pending and injected exceptions for
KVM_GUESTDBG_INJECT_DB and KVM_GUESTDBG_INJECT_BP, to avoid accidentally
injecting a #DB or triple fault.
Signed-off-by: Yosry Ahmed <yosry@kernel.org>
base-commit: a68a4bbc5b9ce5b722473399f05cb05217abaee8
Signed-off-by: Sean Christopherson <seanjc@google.com>
| -rw-r--r-- | arch/x86/kvm/x86.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index a03530795707..658476815b6a 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -12529,7 +12529,7 @@ int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu, if (dbg->control & (KVM_GUESTDBG_INJECT_DB | KVM_GUESTDBG_INJECT_BP)) { r = -EBUSY; - if (kvm_is_exception_pending(vcpu)) + if (kvm_is_exception_pending(vcpu) || vcpu->arch.exception.injected) goto out; if (dbg->control & KVM_GUESTDBG_INJECT_DB) kvm_queue_exception(vcpu, DB_VECTOR); |