The emulation of WFI-like instructions (WFI, PSCI CPU_SUSPEND) is done
by calling kvm_vcpu_block() directly from the respective exit handlers.
A subsequent change to KVM will allow userspace to request a vCPU be
suspended on the next KVM_RUN, necessitating a deferral mechanism for
WFI emulation.
Refactor such that there is a single WFI implementation which may be
requested with KVM_REQ_SUSPEND. Request WFI emulation from the
aforementioned handlers by making this request.
Signed-off-by: Oliver Upton <oupton@xxxxxxxxxx>
---
arch/arm64/include/asm/kvm_host.h | 1 +
arch/arm64/kvm/arm.c | 9 +++++++++
arch/arm64/kvm/handle_exit.c | 3 +--
arch/arm64/kvm/psci.c | 4 +---
4 files changed, 12 insertions(+), 5 deletions(-)
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index f8be56d5342b..1beda1189a15 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -47,6 +47,7 @@
#define KVM_REQ_RECORD_STEAL KVM_ARCH_REQ(3)
#define KVM_REQ_RELOAD_GICv4 KVM_ARCH_REQ(4)
#define KVM_REQ_RELOAD_PMU KVM_ARCH_REQ(5)
+#define KVM_REQ_SUSPEND KVM_ARCH_REQ(6)
#define KVM_DIRTY_LOG_MANUAL_CAPS (KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE | \
KVM_DIRTY_LOG_INITIALLY_SET)
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 3d4acd354f94..f1a375648e25 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -670,6 +670,12 @@ static void kvm_vcpu_sleep(struct kvm_vcpu *vcpu)
smp_rmb();
}
+static void kvm_vcpu_suspend(struct kvm_vcpu *vcpu)
+{
+ kvm_vcpu_block(vcpu);
+ kvm_clear_request(KVM_REQ_UNHALT, vcpu);
+}
+
static int kvm_vcpu_initialized(struct kvm_vcpu *vcpu)
{
return vcpu->arch.target >= 0;
@@ -681,6 +687,9 @@ static void check_vcpu_requests(struct kvm_vcpu *vcpu)
if (kvm_check_request(KVM_REQ_SLEEP, vcpu))
kvm_vcpu_sleep(vcpu);
+ if (kvm_check_request(KVM_REQ_SUSPEND, vcpu))
+ kvm_vcpu_suspend(vcpu);
+
if (kvm_check_request(KVM_REQ_VCPU_RESET, vcpu))
kvm_reset_vcpu(vcpu);
diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c
index 275a27368a04..5e5ef9ff4fba 100644
--- a/arch/arm64/kvm/handle_exit.c
+++ b/arch/arm64/kvm/handle_exit.c
@@ -95,8 +95,7 @@ static int kvm_handle_wfx(struct kvm_vcpu *vcpu)
} else {
trace_kvm_wfx_arm64(*vcpu_pc(vcpu), false);
vcpu->stat.wfi_exit_stat++;
- kvm_vcpu_block(vcpu);
- kvm_clear_request(KVM_REQ_UNHALT, vcpu);
+ kvm_make_request(KVM_REQ_SUSPEND, vcpu);
}
kvm_incr_pc(vcpu);
diff --git a/arch/arm64/kvm/psci.c b/arch/arm64/kvm/psci.c
index bb59b692998b..d453666ddb83 100644
--- a/arch/arm64/kvm/psci.c
+++ b/arch/arm64/kvm/psci.c
@@ -46,9 +46,7 @@ static unsigned long kvm_psci_vcpu_suspend(struct kvm_vcpu *vcpu)
* specification (ARM DEN 0022A). This means all suspend states
* for KVM will preserve the register state.
*/
- kvm_vcpu_block(vcpu);
- kvm_clear_request(KVM_REQ_UNHALT, vcpu);
-
+ kvm_make_request(KVM_REQ_SUSPEND, vcpu);
return PSCI_RET_SUCCESS;
}
--
2.33.0.685.g46640cef36-goog
