On Mon, 22 May 2023 23:18:33 +0100,
Jing Zhang <jingzhangos@xxxxxxxxxx> wrote:
>
> 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 | 12 ++--
> arch/arm64/kvm/arm.c | 6 --
> arch/arm64/kvm/sys_regs.c | 100 ++++++++++++++++++++++++------
> include/kvm/arm_pmu.h | 5 +-
> 4 files changed, 92 insertions(+), 31 deletions(-)
>
> diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
> index 8a2fde6c04c4..7b0f43373dbe 100644
> --- a/arch/arm64/include/asm/kvm_host.h
> +++ b/arch/arm64/include/asm/kvm_host.h
> @@ -246,6 +246,13 @@ struct kvm_arch {
> #define KVM_ARCH_FLAG_TIMER_PPIS_IMMUTABLE 7
> /* SMCCC filter initialized for the VM */
> #define KVM_ARCH_FLAG_SMCCC_FILTER_CONFIGURED 8
> + /*
> + * 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 9
> +
> unsigned long flags;
>
> /*
> @@ -257,11 +264,6 @@ 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;
> struct maple_tree smccc_filter;
> diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
> index 5114521ace60..ca18c09ccf82 100644
> --- a/arch/arm64/kvm/arm.c
> +++ b/arch/arm64/kvm/arm.c
> @@ -148,12 +148,6 @@ 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/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> index 9fb1c2f8f5a5..84d9e4baa4f8 100644
> --- a/arch/arm64/kvm/sys_regs.c
> +++ b/arch/arm64/kvm/sys_regs.c
> @@ -1178,9 +1178,12 @@ static bool access_arch_timer(struct kvm_vcpu *vcpu,
> 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)
> @@ -1403,8 +1406,12 @@ 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;
> + u64 old_val = read_id_reg(vcpu, rd);
> u8 pmuver, host_pmuver;
> + u64 new_val = val;
> bool valid_pmu;
> + int ret = 0;
>
> host_pmuver = kvm_arm_pmu_get_pmuver_limit();
>
> @@ -1424,26 +1431,51 @@ 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 ^= old_val;
> 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 (kvm_vm_has_ran_once(vcpu->kvm)) {
> + if (new_val != old_val)
> + 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;
> + u64 old_val = read_id_reg(vcpu, rd);
> u8 perfmon, host_perfmon;
> + u64 new_val = val;
> bool valid_pmu;
> + int ret = 0;
>
> host_perfmon = pmuver_to_perfmon(kvm_arm_pmu_get_pmuver_limit());
>
> @@ -1464,18 +1496,39 @@ 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 ^= old_val;
> 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 (kvm_vm_has_ran_once(vcpu->kvm)) {
> + if (new_val != old_val)
> + 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);
> + }
> + }
This is the exact same code as for aa64fdr0. Make it a helper, please.
>
> - return 0;
> +out:
> + mutex_unlock(&arch->config_lock);
> + return ret;
> }
>
> /*
> @@ -3422,6 +3475,17 @@ 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;
> }
>
> int __init kvm_sys_reg_table_init(void)
> diff --git a/include/kvm/arm_pmu.h b/include/kvm/arm_pmu.h
> index 1a6a695ca67a..8d70dbdc1e0a 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)
This is getting unreadable. How about something like:
diff --git a/include/kvm/arm_pmu.h b/include/kvm/arm_pmu.h
index 8d70dbdc1e0a..ecb55d87fa36 100644
--- a/include/kvm/arm_pmu.h
+++ b/include/kvm/arm_pmu.h
@@ -92,9 +92,13 @@ 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) \
- (FIELD_GET(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer), \
- IDREG(vcpu->kvm, SYS_ID_AA64DFR0_EL1)) >= ID_AA64DFR0_EL1_PMUVer_V3P5)
+#define kvm_pmu_is_3p5(vcpu) ({ \
+ u64 val = IDREG(vcpu->kvm, SYS_ID_AA64DFR0_EL1); \
+ u8 v; \
+ \
+ v = FIELD_GET(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer), val); \
+ v >= ID_AA64DFR0_EL1_PMUVer_V3P5; \
+})
u8 kvm_arm_pmu_get_pmuver_limit(void);
Thanks,
M.
--
Without deviation from the norm, progress is not possible.
