[PATCH v2 14/19] KVM: arm64: Convert vcpu sysregs_loaded_on_cpu to a state flag

Marc Zyngier
2022-06-10T09:35:46Z

The aptly named boolean 'sysregs_loaded_on_cpu' tracks whether
some of the vcpu system registers are resident on the physical
CPU when running in VHE mode.

This is obviously a flag in hidding, so let's convert it to
a state flag, since this is solely a host concern (the hypervisor
itself always knows which state we're in).

Reviewed-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
---
arch/arm64/include/asm/kvm_host.h | 6 ++----
arch/arm64/kvm/hyp/vhe/sysreg-sr.c | 4 ++--
arch/arm64/kvm/sys_regs.c | 4 ++--
3 files changed, 6 insertions(+), 8 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 39da28f85045..ffbeb5f5692e 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -410,10 +410,6 @@ struct kvm_vcpu_arch {
/* Additional reset state */
struct vcpu_reset_state reset_state;

- /* True when deferrable sysregs are loaded on the physical CPU,
- * see kvm_vcpu_load_sysregs_vhe and kvm_vcpu_put_sysregs_vhe. */
- bool sysregs_loaded_on_cpu;
-
/* Guest PV state */
struct {
u64 last_steal;
@@ -520,6 +516,8 @@ struct kvm_vcpu_arch {
#define ON_UNSUPPORTED_CPU __vcpu_single_flag(sflags, BIT(2))
/* WFIT instruction trapped */
#define IN_WFIT __vcpu_single_flag(sflags, BIT(3))
+/* vcpu system registers loaded on physical CPU */
+#define SYSREGS_ON_CPU __vcpu_single_flag(sflags, BIT(4))

/* 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/hyp/vhe/sysreg-sr.c b/arch/arm64/kvm/hyp/vhe/sysreg-sr.c
index 007a12dd4351..7b44f6b3b547 100644
--- a/arch/arm64/kvm/hyp/vhe/sysreg-sr.c
+++ b/arch/arm64/kvm/hyp/vhe/sysreg-sr.c
@@ -79,7 +79,7 @@ void kvm_vcpu_load_sysregs_vhe(struct kvm_vcpu *vcpu)
__sysreg_restore_user_state(guest_ctxt);
__sysreg_restore_el1_state(guest_ctxt);

- vcpu->arch.sysregs_loaded_on_cpu = true;
+ vcpu_set_flag(vcpu, SYSREGS_ON_CPU);

activate_traps_vhe_load(vcpu);
}
@@ -110,5 +110,5 @@ void kvm_vcpu_put_sysregs_vhe(struct kvm_vcpu *vcpu)
/* Restore host user state */
__sysreg_restore_user_state(host_ctxt);

- vcpu->arch.sysregs_loaded_on_cpu = false;
+ vcpu_clear_flag(vcpu, SYSREGS_ON_CPU);
}
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index f24797c57df8..1c562bcfeccf 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -72,7 +72,7 @@ u64 vcpu_read_sys_reg(const struct kvm_vcpu *vcpu, int reg)
{
u64 val = 0x8badf00d8badf00d;

- if (vcpu->arch.sysregs_loaded_on_cpu &&
+ if (vcpu_get_flag(vcpu, SYSREGS_ON_CPU) &&
__vcpu_read_sys_reg_from_cpu(reg, &val))
return val;

@@ -81,7 +81,7 @@ u64 vcpu_read_sys_reg(const struct kvm_vcpu *vcpu, int reg)

void vcpu_write_sys_reg(struct kvm_vcpu *vcpu, u64 val, int reg)
{
- if (vcpu->arch.sysregs_loaded_on_cpu &&
+ if (vcpu_get_flag(vcpu, SYSREGS_ON_CPU) &&
__vcpu_write_sys_reg_to_cpu(val, reg))
return;

--
2.34.1