KVM: mips, x86: do not rely on KVM_REQ_UNHALT

KVM_REQ_UNHALT is a weird request that simply reports the value of
kvm_arch_vcpu_runnable() on exit from kvm_vcpu_halt().  Only
MIPS and x86 are looking at it, the others just clear it.  Check
the state of the vCPU directly so that the request is handled
as a nop on all architectures.

No functional change intended, except for corner cases where an
event arrive immediately after a signal become pending or after
another similar host-side event.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20220921003201.1441511-12-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/mips/kvm/emulate.c b/arch/mips/kvm/emulate.c
index b494d8d..1d7c56d 100644 (file)
--- a/arch/mips/kvm/emulate.c
+++ b/arch/mips/kvm/emulate.c
@@ -955,13 +955,12 @@ enum emulation_result kvm_mips_emul_wait(struct kvm_vcpu *vcpu)
                kvm_vcpu_halt(vcpu);
 
                /*
-                * We we are runnable, then definitely go off to user space to
+                * We are runnable, then definitely go off to user space to
                 * check if any I/O interrupts are pending.
                 */
-               if (kvm_check_request(KVM_REQ_UNHALT, vcpu)) {
-                       kvm_clear_request(KVM_REQ_UNHALT, vcpu);
+               kvm_clear_request(KVM_REQ_UNHALT, vcpu);
+               if (kvm_arch_vcpu_runnable(vcpu))
                        vcpu->run->exit_reason = KVM_EXIT_IRQ_WINDOW_OPEN;
-               }
        }
 
        return EMULATE_DONE;

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index f1e416e..20c56be 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -10813,7 +10813,14 @@ static inline int vcpu_block(struct kvm_vcpu *vcpu)
                if (hv_timer)
                        kvm_lapic_switch_to_hv_timer(vcpu);
 
-               if (!kvm_check_request(KVM_REQ_UNHALT, vcpu))
+               kvm_clear_request(KVM_REQ_UNHALT, vcpu);
+
+               /*
+                * If the vCPU is not runnable, a signal or another host event
+                * of some kind is pending; service it without changing the
+                * vCPU's activity state.
+                */
+               if (!kvm_arch_vcpu_runnable(vcpu))
                        return 1;
        }