KVM: x86: Drop redundant call to kvm_deliver_exception_payload()

Browse source

In kvm_check_and_inject_events(), kvm_deliver_exception_payload() is
called for pending #DB exceptions. However, shortly after, the
per-vendor inject_exception callbacks are made. Both
vmx_inject_exception() and svm_inject_exception() unconditionally call
kvm_deliver_exception_payload(), so the call in
kvm_check_and_inject_events() is redundant.

Note that the extra call for pending #DB exceptions is harmless, as
kvm_deliver_exception_payload() clears exception.has_payload after the
first call.

The call in kvm_check_and_inject_events() was added in commit
f10c729ff9 ("kvm: vmx: Defer setting of DR6 until #DB delivery"). At
that point, the call was likely needed because svm_queue_exception()
checked whether an exception for L2 is intercepted by L1 before calling
kvm_deliver_exception_payload(), as SVM did not have a
check_nested_events callback. Since DR6 is updated before the #DB
intercept in SVM (unlike VMX), it was necessary to deliver the DR6
payload before calling svm_queue_exception().

After that, commit 7c86663b68 ("KVM: nSVM: inject exceptions via
svm_check_nested_events") added a check_nested_events callback for SVM,
which checked for L1 intercepts for L2's exceptions, and delivered the
the payload appropriately before the intercept. At that point,
svm_queue_exception() started calling kvm_deliver_exception_payload()
unconditionally, and the call to kvm_deliver_exception_payload() from
its caller became redundant.

No functional change intended.

Signed-off-by: Yosry Ahmed <yosry@kernel.org>
Link: https://patch.msgid.link/20260302154249.784529-1-yosry@kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>

...

This commit is contained in:

Yosry Ahmed 2026-03-02 15:42:49 +00:00 • committed by Sean Christopherson

parent 690dc03859

commit 43e41846ac

1 changed files with 4 additions and 6 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

10

arch/x86/kvm/x86.c

View file