[PATCH MANUALSEL 5.14 3/5] KVM: VMX: Remove redundant handling of bus lock vmexit
From: Sasha Levin <sashal@kernel.org>
Date: 2021-10-25 20:38:51
Also in:
kvm, lkml
Subsystem:
kernel virtual machine for x86 (kvm/x86), the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Sean Christopherson, Paolo Bonzini, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
From: Hao Xiang <redacted> [ Upstream commit d61863c66f9b443192997613cd6aeca3f65cc313 ] Hardware may or may not set exit_reason.bus_lock_detected on BUS_LOCK VM-Exits. Dealing with KVM_RUN_X86_BUS_LOCK in handle_bus_lock_vmexit could be redundant when exit_reason.basic is EXIT_REASON_BUS_LOCK. We can remove redundant handling of bus lock vmexit. Unconditionally Set exit_reason.bus_lock_detected in handle_bus_lock_vmexit(), and deal with KVM_RUN_X86_BUS_LOCK only in vmx_handle_exit(). Signed-off-by: Hao Xiang <redacted> Message-Id: [off-list ref] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org> --- arch/x86/kvm/vmx/vmx.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-)
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 55de1eb135f9..87150b3c9c5f 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c@@ -5551,9 +5551,13 @@ static int handle_encls(struct kvm_vcpu *vcpu) static int handle_bus_lock_vmexit(struct kvm_vcpu *vcpu) { - vcpu->run->exit_reason = KVM_EXIT_X86_BUS_LOCK; - vcpu->run->flags |= KVM_RUN_X86_BUS_LOCK; - return 0; + /* + * Hardware may or may not set the BUS_LOCK_DETECTED flag on BUS_LOCK + * VM-Exits. Unconditionally set the flag here and leave the handling to + * vmx_handle_exit(). + */ + to_vmx(vcpu)->exit_reason.bus_lock_detected = true; + return 1; } /*
@@ -6039,9 +6043,8 @@ static int vmx_handle_exit(struct kvm_vcpu *vcpu, fastpath_t exit_fastpath) int ret = __vmx_handle_exit(vcpu, exit_fastpath); /* - * Even when current exit reason is handled by KVM internally, we - * still need to exit to user space when bus lock detected to inform - * that there is a bus lock in guest. + * Exit to user space when bus lock detected to inform that there is + * a bus lock in guest. */ if (to_vmx(vcpu)->exit_reason.bus_lock_detected) { if (ret > 0)
--
2.33.0