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arm64: KVM: Add access handler for PMCNTENSET and PMCNTENCLR register 

Since the reset value of PMCNTENSET and PMCNTENCLR is UNKNOWN, use
reset_unknown for its reset handler. Add a handler to emulate writing
PMCNTENSET or PMCNTENCLR register.

When writing to PMCNTENSET, call perf_event_enable to enable the perf
event. When writing to PMCNTENCLR, call perf_event_disable to disable
the perf event.

Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
This commit is contained in:
Shannon Zhao 2015-09-08 12:26:13 +08:00 committed by Marc Zyngier
parent 051ff581ce
commit 96b0eebcc6
4 changed files with 107 additions and 4 deletions
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1
arch/arm64/include/asm/kvm_host.h
View File

@ -123,6 +123,7 @@ enum vcpu_sysreg {
PMEVCNTR0_EL0, /* Event Counter Register (0-30) */
PMEVCNTR30_EL0 = PMEVCNTR0_EL0 + 30,
PMCCNTR_EL0, /* Cycle Counter Register */
PMCNTENSET_EL0, /* Count Enable Set Register */
/* 32bit specific registers. Keep them at the end of the range */
DACR32_EL2, /* Domain Access Control Register */

35
arch/arm64/kvm/sys_regs.c
View File

@ -563,6 +563,33 @@ static bool access_pmu_evcntr(struct kvm_vcpu *vcpu,
return true;
}
static bool access_pmcnten(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
const struct sys_reg_desc *r)
{
u64 val, mask;
if (!kvm_arm_pmu_v3_ready(vcpu))
return trap_raz_wi(vcpu, p, r);
mask = kvm_pmu_valid_counter_mask(vcpu);
if (p->is_write) {
val = p->regval & mask;
if (r->Op2 & 0x1) {
/* accessing PMCNTENSET_EL0 */
vcpu_sys_reg(vcpu, PMCNTENSET_EL0) |= val;
kvm_pmu_enable_counter(vcpu, val);
} else {
/* accessing PMCNTENCLR_EL0 */
vcpu_sys_reg(vcpu, PMCNTENSET_EL0) &= ~val;
kvm_pmu_disable_counter(vcpu, val);
}
} else {
p->regval = vcpu_sys_reg(vcpu, PMCNTENSET_EL0) & mask;
}
return true;
}
/* Silly macro to expand the DBG{BCR,BVR,WVR,WCR}n_EL1 registers in one go */
#define DBG_BCR_BVR_WCR_WVR_EL1(n) \
/* DBGBVRn_EL1 */ \
@ -757,10 +784,10 @@ static const struct sys_reg_desc sys_reg_descs[] = {
access_pmcr, reset_pmcr, },
/* PMCNTENSET_EL0 */
{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1100), Op2(0b001),
trap_raz_wi },
access_pmcnten, reset_unknown, PMCNTENSET_EL0 },
/* PMCNTENCLR_EL0 */
{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1100), Op2(0b010),
trap_raz_wi },
access_pmcnten, NULL, PMCNTENSET_EL0 },
/* PMOVSCLR_EL0 */
{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1100), Op2(0b011),
trap_raz_wi },
@ -1057,8 +1084,8 @@ static const struct sys_reg_desc cp15_regs[] = {
/* PMU */
{ Op1( 0), CRn( 9), CRm(12), Op2( 0), access_pmcr },
{ Op1( 0), CRn( 9), CRm(12), Op2( 1), trap_raz_wi },
{ Op1( 0), CRn( 9), CRm(12), Op2( 2), trap_raz_wi },
{ Op1( 0), CRn( 9), CRm(12), Op2( 1), access_pmcnten },
{ Op1( 0), CRn( 9), CRm(12), Op2( 2), access_pmcnten },
{ Op1( 0), CRn( 9), CRm(12), Op2( 3), trap_raz_wi },
{ Op1( 0), CRn( 9), CRm(12), Op2( 5), access_pmselr },
{ Op1( 0), CRn( 9), CRm(12), Op2( 6), access_pmceid },

9
include/kvm/arm_pmu.h
View File

@ -40,6 +40,9 @@ struct kvm_pmu {
#define kvm_arm_pmu_v3_ready(v) ((v)->arch.pmu.ready)
u64 kvm_pmu_get_counter_value(struct kvm_vcpu *vcpu, u64 select_idx);
void kvm_pmu_set_counter_value(struct kvm_vcpu *vcpu, u64 select_idx, u64 val);
u64 kvm_pmu_valid_counter_mask(struct kvm_vcpu *vcpu);
void kvm_pmu_disable_counter(struct kvm_vcpu *vcpu, u64 val);
void kvm_pmu_enable_counter(struct kvm_vcpu *vcpu, u64 val);
#else
struct kvm_pmu {
};
@ -52,6 +55,12 @@ static inline u64 kvm_pmu_get_counter_value(struct kvm_vcpu *vcpu,
}
static inline void kvm_pmu_set_counter_value(struct kvm_vcpu *vcpu,
u64 select_idx, u64 val) {}
static inline u64 kvm_pmu_valid_counter_mask(struct kvm_vcpu *vcpu)
{
return 0;
}
static inline void kvm_pmu_disable_counter(struct kvm_vcpu *vcpu, u64 val) {}
static inline void kvm_pmu_enable_counter(struct kvm_vcpu *vcpu, u64 val) {}
#endif
#endif

66
virt/kvm/arm/pmu.c
View File

@ -61,3 +61,69 @@ void kvm_pmu_set_counter_value(struct kvm_vcpu *vcpu, u64 select_idx, u64 val)
? PMCCNTR_EL0 : PMEVCNTR0_EL0 + select_idx;
vcpu_sys_reg(vcpu, reg) += (s64)val - kvm_pmu_get_counter_value(vcpu, select_idx);
}
u64 kvm_pmu_valid_counter_mask(struct kvm_vcpu *vcpu)
{
u64 val = vcpu_sys_reg(vcpu, PMCR_EL0) >> ARMV8_PMU_PMCR_N_SHIFT;
val &= ARMV8_PMU_PMCR_N_MASK;
if (val == 0)
return BIT(ARMV8_PMU_CYCLE_IDX);
else
return GENMASK(val - 1, 0) | BIT(ARMV8_PMU_CYCLE_IDX);
}
/**
* kvm_pmu_enable_counter - enable selected PMU counter
* @vcpu: The vcpu pointer
* @val: the value guest writes to PMCNTENSET register
*
* Call perf_event_enable to start counting the perf event
*/
void kvm_pmu_enable_counter(struct kvm_vcpu *vcpu, u64 val)
{
int i;
struct kvm_pmu *pmu = &vcpu->arch.pmu;
struct kvm_pmc *pmc;
if (!(vcpu_sys_reg(vcpu, PMCR_EL0) & ARMV8_PMU_PMCR_E) || !val)
return;
for (i = 0; i < ARMV8_PMU_MAX_COUNTERS; i++) {
if (!(val & BIT(i)))
continue;
pmc = &pmu->pmc[i];
if (pmc->perf_event) {
perf_event_enable(pmc->perf_event);
if (pmc->perf_event->state != PERF_EVENT_STATE_ACTIVE)
kvm_debug("fail to enable perf event\n");
}
}
}
/**
* kvm_pmu_disable_counter - disable selected PMU counter
* @vcpu: The vcpu pointer
* @val: the value guest writes to PMCNTENCLR register
*
* Call perf_event_disable to stop counting the perf event
*/
void kvm_pmu_disable_counter(struct kvm_vcpu *vcpu, u64 val)
{
int i;
struct kvm_pmu *pmu = &vcpu->arch.pmu;
struct kvm_pmc *pmc;
if (!val)
return;
for (i = 0; i < ARMV8_PMU_MAX_COUNTERS; i++) {
if (!(val & BIT(i)))
continue;
pmc = &pmu->pmc[i];
if (pmc->perf_event)
perf_event_disable(pmc->perf_event);
}
}