WIP
Signed-off-by: Marc Zyngier <maz@kernel.org>
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index a33f599..2615946 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -686,7 +686,7 @@ struct kvm_vcpu_arch {
u8 iflags;
/* State flags for kernel bookkeeping, unused by the hypervisor code */
- u8 sflags;
+ u16 sflags;
/*
* Don't run the guest (internal implementation need).
@@ -895,7 +895,8 @@ struct kvm_vcpu_arch {
#define PMUSERENR_ON_CPU __vcpu_single_flag(sflags, BIT(6))
/* WFI instruction trapped */
#define IN_WFI __vcpu_single_flag(sflags, BIT(7))
-
+/* Non-preemptible put/load transition */
+#define TRANSIENT_PUT_LOAD __vcpu_single_flag(sflags, BIT(8))
/* Pointer to the vcpu's SVE FFR for sve_{save,load}_state() */
#define vcpu_sve_pffr(vcpu) (kern_hyp_va((vcpu)->arch.sve_state) + \
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index a7ca776..8481c1af 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -606,7 +606,8 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
kvm_timer_vcpu_load(vcpu);
if (has_vhe())
kvm_vcpu_load_vhe(vcpu);
- kvm_arch_vcpu_load_fp(vcpu);
+ if (!vcpu_get_flag(vcpu, TRANSIENT_PUT_LOAD))
+ kvm_arch_vcpu_load_fp(vcpu);
kvm_vcpu_pmu_restore_guest(vcpu);
if (kvm_arm_is_pvtime_enabled(&vcpu->arch))
kvm_make_request(KVM_REQ_RECORD_STEAL, vcpu);
@@ -632,7 +633,8 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
{
kvm_arch_vcpu_put_debug_state_flags(vcpu);
- kvm_arch_vcpu_put_fp(vcpu);
+ if (!vcpu_get_flag(vcpu, TRANSIENT_PUT_LOAD))
+ kvm_arch_vcpu_put_fp(vcpu);
if (has_vhe())
kvm_vcpu_put_vhe(vcpu);
kvm_timer_vcpu_put(vcpu);
diff --git a/arch/arm64/kvm/emulate-nested.c b/arch/arm64/kvm/emulate-nested.c
index e384913..bccb3a1 100644
--- a/arch/arm64/kvm/emulate-nested.c
+++ b/arch/arm64/kvm/emulate-nested.c
@@ -2300,11 +2300,16 @@ static void nested_switch(struct kvm_vcpu *vcpu, nv_switch_fn fn, const union nv
if (!is_hyp_ctxt(vcpu))
__kvm_adjust_pc(vcpu);
+ vcpu_set_flag(vcpu, TRANSIENT_PUT_LOAD);
+
kvm_arch_vcpu_put(vcpu);
fn(vcpu, data);
kvm_arch_vcpu_load(vcpu, smp_processor_id());
+
+ vcpu_clear_flag(vcpu, TRANSIENT_PUT_LOAD);
+
preempt_enable();
}
