With per guest ID registers, PMUver settings from userspace
can be stored in its corresponding ID register.
No functional change intended.
Signed-off-by: Jing Zhang <jingzhangos@xxxxxxxxxx>
---
arch/arm64/include/asm/kvm_host.h | 11 ++--
arch/arm64/kvm/arm.c | 6 --
arch/arm64/kvm/id_regs.c | 94 +++++++++++++++++++++++++------
include/kvm/arm_pmu.h | 5 +-
4 files changed, 87 insertions(+), 29 deletions(-)
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 4699f6b829b2..009f6ff41078 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -236,6 +236,12 @@ struct kvm_arch {
#define KVM_ARCH_FLAG_EL1_32BIT 4
/* PSCI SYSTEM_SUSPEND enabled for the guest */
#define KVM_ARCH_FLAG_SYSTEM_SUSPEND_ENABLED 5
+ /*
+ * AA64DFR0_EL1.PMUver was set as ID_AA64DFR0_EL1_PMUVer_IMP_DEF
+ * or DFR0_EL1.PerfMon was set as ID_DFR0_EL1_PerfMon_IMPDEF from
+ * userspace for VCPUs without PMU.
+ */
+#define KVM_ARCH_FLAG_VCPU_HAS_IMP_DEF_PMU 6
unsigned long flags;
@@ -248,11 +254,6 @@ struct kvm_arch {
cpumask_var_t supported_cpus;
- struct {
- u8 imp:4;
- u8 unimp:4;
- } dfr0_pmuver;
-
/* Hypercall features firmware registers' descriptor */
struct kvm_smccc_features smccc_feat;
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 0f71b10a2f05..9ecd0c5d0754 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -138,12 +138,6 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
kvm_arm_init_hypercalls(kvm);
kvm_arm_init_id_regs(kvm);
- /*
- * Initialise the default PMUver before there is a chance to
- * create an actual PMU.
- */
- kvm->arch.dfr0_pmuver.imp = kvm_arm_pmu_get_pmuver_limit();
-
return 0;
err_free_cpumask:
diff --git a/arch/arm64/kvm/id_regs.c b/arch/arm64/kvm/id_regs.c
index 5e0fd4c8b375..0a04a90a8676 100644
--- a/arch/arm64/kvm/id_regs.c
+++ b/arch/arm64/kvm/id_regs.c
@@ -21,9 +21,12 @@
static u8 vcpu_pmuver(const struct kvm_vcpu *vcpu)
{
if (kvm_vcpu_has_pmu(vcpu))
- return vcpu->kvm->arch.dfr0_pmuver.imp;
+ return FIELD_GET(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer),
+ IDREG(vcpu->kvm, SYS_ID_AA64DFR0_EL1));
+ else if (test_bit(KVM_ARCH_FLAG_VCPU_HAS_IMP_DEF_PMU, &vcpu->kvm->arch.flags))
+ return ID_AA64DFR0_EL1_PMUVer_IMP_DEF;
- return vcpu->kvm->arch.dfr0_pmuver.unimp;
+ return 0;
}
static u8 perfmon_to_pmuver(u8 perfmon)
@@ -244,8 +247,11 @@ static int set_id_aa64dfr0_el1(struct kvm_vcpu *vcpu,
const struct sys_reg_desc *rd,
u64 val)
{
+ struct kvm_arch *arch = &vcpu->kvm->arch;
u8 pmuver, host_pmuver;
bool valid_pmu;
+ u64 sval = val;
+ int ret = 0;
host_pmuver = kvm_arm_pmu_get_pmuver_limit();
@@ -265,26 +271,50 @@ static int set_id_aa64dfr0_el1(struct kvm_vcpu *vcpu,
if (kvm_vcpu_has_pmu(vcpu) != valid_pmu)
return -EINVAL;
+ mutex_lock(&arch->config_lock);
/* We can only differ with PMUver, and anything else is an error */
val ^= read_id_reg(vcpu, rd);
val &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer);
- if (val)
- return -EINVAL;
+ if (val) {
+ ret = -EINVAL;
+ goto out;
+ }
- if (valid_pmu)
- vcpu->kvm->arch.dfr0_pmuver.imp = pmuver;
- else
- vcpu->kvm->arch.dfr0_pmuver.unimp = pmuver;
+ /* Only allow userspace to change the idregs before VM running */
+ if (test_bit(KVM_ARCH_FLAG_HAS_RAN_ONCE, &vcpu->kvm->arch.flags)) {
+ if (sval != read_id_reg(vcpu, rd))
+ ret = -EBUSY;
+ } else {
+ if (valid_pmu) {
+ val = IDREG(vcpu->kvm, SYS_ID_AA64DFR0_EL1);
+ val &= ~ID_AA64DFR0_EL1_PMUVer_MASK;
+ val |= FIELD_PREP(ID_AA64DFR0_EL1_PMUVer_MASK, pmuver);
+ IDREG(vcpu->kvm, SYS_ID_AA64DFR0_EL1) = val;
+
+ val = IDREG(vcpu->kvm, SYS_ID_DFR0_EL1);
+ val &= ~ID_DFR0_EL1_PerfMon_MASK;
+ val |= FIELD_PREP(ID_DFR0_EL1_PerfMon_MASK, pmuver_to_perfmon(pmuver));
+ IDREG(vcpu->kvm, SYS_ID_DFR0_EL1) = val;
+ } else {
+ assign_bit(KVM_ARCH_FLAG_VCPU_HAS_IMP_DEF_PMU, &vcpu->kvm->arch.flags,
+ pmuver == ID_AA64DFR0_EL1_PMUVer_IMP_DEF);
+ }
+ }
- return 0;
+out:
+ mutex_unlock(&arch->config_lock);
+ return ret;
}
static int set_id_dfr0_el1(struct kvm_vcpu *vcpu,
const struct sys_reg_desc *rd,
u64 val)
{
+ struct kvm_arch *arch = &vcpu->kvm->arch;
u8 perfmon, host_perfmon;
bool valid_pmu;
+ u64 sval = val;
+ int ret = 0;
host_perfmon = pmuver_to_perfmon(kvm_arm_pmu_get_pmuver_limit());
@@ -305,18 +335,39 @@ static int set_id_dfr0_el1(struct kvm_vcpu *vcpu,
if (kvm_vcpu_has_pmu(vcpu) != valid_pmu)
return -EINVAL;
+ mutex_lock(&arch->config_lock);
/* We can only differ with PerfMon, and anything else is an error */
val ^= read_id_reg(vcpu, rd);
val &= ~ARM64_FEATURE_MASK(ID_DFR0_EL1_PerfMon);
- if (val)
- return -EINVAL;
+ if (val) {
+ ret = -EINVAL;
+ goto out;
+ }
- if (valid_pmu)
- vcpu->kvm->arch.dfr0_pmuver.imp = perfmon_to_pmuver(perfmon);
- else
- vcpu->kvm->arch.dfr0_pmuver.unimp = perfmon_to_pmuver(perfmon);
+ /* Only allow userspace to change the idregs before VM running */
+ if (test_bit(KVM_ARCH_FLAG_HAS_RAN_ONCE, &vcpu->kvm->arch.flags)) {
+ if (sval != read_id_reg(vcpu, rd))
+ ret = -EBUSY;
+ } else {
+ if (valid_pmu) {
+ val = IDREG(vcpu->kvm, SYS_ID_DFR0_EL1);
+ val &= ~ID_DFR0_EL1_PerfMon_MASK;
+ val |= FIELD_PREP(ID_DFR0_EL1_PerfMon_MASK, perfmon);
+ IDREG(vcpu->kvm, SYS_ID_DFR0_EL1) = val;
+
+ val = IDREG(vcpu->kvm, SYS_ID_AA64DFR0_EL1);
+ val &= ~ID_AA64DFR0_EL1_PMUVer_MASK;
+ val |= FIELD_PREP(ID_AA64DFR0_EL1_PMUVer_MASK, perfmon_to_pmuver(perfmon));
+ IDREG(vcpu->kvm, SYS_ID_AA64DFR0_EL1) = val;
+ } else {
+ assign_bit(KVM_ARCH_FLAG_VCPU_HAS_IMP_DEF_PMU, &vcpu->kvm->arch.flags,
+ perfmon == ID_DFR0_EL1_PerfMon_IMPDEF);
+ }
+ }
- return 0;
+out:
+ mutex_unlock(&arch->config_lock);
+ return ret;
}
/* sys_reg_desc initialiser for known cpufeature ID registers */
@@ -517,4 +568,15 @@ void kvm_arm_init_id_regs(struct kvm *kvm)
}
IDREG(kvm, SYS_ID_AA64PFR0_EL1) = val;
+ /*
+ * Initialise the default PMUver before there is a chance to
+ * create an actual PMU.
+ */
+ val = IDREG(kvm, SYS_ID_AA64DFR0_EL1);
+
+ val &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer);
+ val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer),
+ kvm_arm_pmu_get_pmuver_limit());
+
+ IDREG(kvm, SYS_ID_AA64DFR0_EL1) = val;
}
diff --git a/include/kvm/arm_pmu.h b/include/kvm/arm_pmu.h
index 628775334d5e..e486347b297d 100644
--- a/include/kvm/arm_pmu.h
+++ b/include/kvm/arm_pmu.h
@@ -92,8 +92,9 @@ void kvm_vcpu_pmu_restore_host(struct kvm_vcpu *vcpu);
/*
* Evaluates as true when emulating PMUv3p5, and false otherwise.
*/
-#define kvm_pmu_is_3p5(vcpu) \
- (vcpu->kvm->arch.dfr0_pmuver.imp >= ID_AA64DFR0_EL1_PMUVer_V3P5)
+#define kvm_pmu_is_3p5(vcpu) \
+ (FIELD_GET(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer), \
+ IDREG(vcpu->kvm, SYS_ID_AA64DFR0_EL1)) >= ID_AA64DFR0_EL1_PMUVer_V3P5)
u8 kvm_arm_pmu_get_pmuver_limit(void);
--
2.40.1.495.gc816e09b53d-goog
