[PATCH v4 12/23] KVM: arm64: Writethrough trapped PMOVS register

[Colton Lewis]

With FGT in place, the remaining trapped registers need to be written
through to the underlying physical registers as well as the virtual
ones. Failing to do this means delaying when guest writes take effect.

Signed-off-by: Colton Lewis <coltonlewis at google.com>
---
 arch/arm64/include/asm/arm_pmuv3.h | 10 ++++++++++
 arch/arm64/kvm/sys_regs.c          | 17 ++++++++++++++++-
 2 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/arm_pmuv3.h b/arch/arm64/include/asm/arm_pmuv3.h
index 60600f04b590..3e25c0313263 100644
--- a/arch/arm64/include/asm/arm_pmuv3.h
+++ b/arch/arm64/include/asm/arm_pmuv3.h
@@ -140,6 +140,16 @@ static inline u64 read_pmicfiltr(void)
 	return read_sysreg_s(SYS_PMICFILTR_EL0);
 }
 
+static inline void write_pmovsset(u64 val)
+{
+	write_sysreg(val, pmovsset_el0);
+}
+
+static inline u64 read_pmovsset(void)
+{
+	return read_sysreg(pmovsset_el0);
+}
+
 static inline void write_pmovsclr(u64 val)
 {
 	write_sysreg(val, pmovsclr_el0);
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index e761538e1e17..68457655a10b 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -1171,6 +1171,19 @@ static bool access_pminten(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
 	return true;
 }
 
+static void writethrough_pmovs(struct kvm_vcpu *vcpu, struct sys_reg_params *p, bool set)
+{
+	u64 mask = kvm_pmu_accessible_counter_mask(vcpu);
+
+	if (set) {
+		__vcpu_rmw_sys_reg(vcpu, PMOVSSET_EL0, |=, (p->regval & mask));
+		write_pmovsset(p->regval & mask);
+	} else {
+		__vcpu_rmw_sys_reg(vcpu, PMOVSSET_EL0, &=, ~(p->regval & mask));
+		write_pmovsclr(p->regval & mask);
+	}
+}
+
 static bool access_pmovs(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
 			 const struct sys_reg_desc *r)
 {
@@ -1179,7 +1192,9 @@ static bool access_pmovs(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
 	if (pmu_access_el0_disabled(vcpu))
 		return false;
 
-	if (p->is_write) {
+	if (kvm_vcpu_pmu_is_partitioned(vcpu) && p->is_write) {
+		writethrough_pmovs(vcpu, p, r->CRm & 0x2);
+	} else if (p->is_write) {
 		if (r->CRm & 0x2)
 			/* accessing PMOVSSET_EL0 */
 			__vcpu_rmw_sys_reg(vcpu, PMOVSSET_EL0, |=, (p->regval & mask));
-- 
2.50.0.727.gbf7dc18ff4-goog