Commit 9800c24e authored by Paolo Bonzini's avatar Paolo Bonzini
Browse files

Merge tag 'kvmarm-fixes-5.4-2' of... 

Merge tag 'kvmarm-fixes-5.4-2' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

KVM/arm fixes for 5.4, take #2

Special PMU edition:

- Fix cycle counter truncation
- Fix cycle counter overflow limit on pure 64bit system
- Allow chained events to be actually functional
- Correct sample period after overflow
parents 49dedf0d 8c3252c0

arch/arm64/kvm/sys_regs.c

+4 −0
Original line number Diff line number Diff line
@@ -632,6 +632,8 @@ static void reset_pmcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r) 
	 */

	val = ((pmcr & ~ARMV8_PMU_PMCR_MASK)

	       | (ARMV8_PMU_PMCR_MASK & 0xdecafbad)) & (~ARMV8_PMU_PMCR_E);

	if (!system_supports_32bit_el0())

		val |= ARMV8_PMU_PMCR_LC;

	__vcpu_sys_reg(vcpu, r->reg) = val;

}
@@ -682,6 +684,8 @@ static bool access_pmcr(struct kvm_vcpu *vcpu, struct sys_reg_params *p, 
		val = __vcpu_sys_reg(vcpu, PMCR_EL0);

		val &= ~ARMV8_PMU_PMCR_MASK;

		val |= p->regval & ARMV8_PMU_PMCR_MASK;

		if (!system_supports_32bit_el0())

			val |= ARMV8_PMU_PMCR_LC;

		__vcpu_sys_reg(vcpu, PMCR_EL0) = val;

		kvm_pmu_handle_pmcr(vcpu, val);

		kvm_vcpu_pmu_restore_guest(vcpu);

virt/kvm/arm/pmu.c

+35 −13
Original line number Diff line number Diff line
@@ -8,6 +8,7 @@ 
#include <linux/kvm.h>

#include <linux/kvm_host.h>

#include <linux/perf_event.h>

#include <linux/perf/arm_pmu.h>

#include <linux/uaccess.h>

#include <asm/kvm_emulate.h>

#include <kvm/arm_pmu.h>
@@ -146,8 +147,7 @@ u64 kvm_pmu_get_counter_value(struct kvm_vcpu *vcpu, u64 select_idx) 
	if (kvm_pmu_pmc_is_chained(pmc) &&

	    kvm_pmu_idx_is_high_counter(select_idx))

		counter = upper_32_bits(counter);



	else if (!kvm_pmu_idx_is_64bit(vcpu, select_idx))

	else if (select_idx != ARMV8_PMU_CYCLE_IDX)

		counter = lower_32_bits(counter);



	return counter;
@@ -193,7 +193,7 @@ static void kvm_pmu_release_perf_event(struct kvm_pmc *pmc) 
 */

static void kvm_pmu_stop_counter(struct kvm_vcpu *vcpu, struct kvm_pmc *pmc)

{

	u64 counter, reg;

	u64 counter, reg, val;



	pmc = kvm_pmu_get_canonical_pmc(pmc);

	if (!pmc->perf_event)
@@ -201,16 +201,19 @@ static void kvm_pmu_stop_counter(struct kvm_vcpu *vcpu, struct kvm_pmc *pmc) 


	counter = kvm_pmu_get_pair_counter_value(vcpu, pmc);



	if (kvm_pmu_pmc_is_chained(pmc)) {

		reg = PMEVCNTR0_EL0 + pmc->idx;

		__vcpu_sys_reg(vcpu, reg) = lower_32_bits(counter);

		__vcpu_sys_reg(vcpu, reg + 1) = upper_32_bits(counter);

	if (pmc->idx == ARMV8_PMU_CYCLE_IDX) {

		reg = PMCCNTR_EL0;

		val = counter;

	} else {

		reg = (pmc->idx == ARMV8_PMU_CYCLE_IDX)

		       ? PMCCNTR_EL0 : PMEVCNTR0_EL0 + pmc->idx;

		__vcpu_sys_reg(vcpu, reg) = lower_32_bits(counter);

		reg = PMEVCNTR0_EL0 + pmc->idx;

		val = lower_32_bits(counter);

	}



	__vcpu_sys_reg(vcpu, reg) = val;



	if (kvm_pmu_pmc_is_chained(pmc))

		__vcpu_sys_reg(vcpu, reg + 1) = upper_32_bits(counter);



	kvm_pmu_release_perf_event(pmc);

}
@@ -440,8 +443,25 @@ static void kvm_pmu_perf_overflow(struct perf_event *perf_event, 
				  struct pt_regs *regs)

{

	struct kvm_pmc *pmc = perf_event->overflow_handler_context;

	struct arm_pmu *cpu_pmu = to_arm_pmu(perf_event->pmu);

	struct kvm_vcpu *vcpu = kvm_pmc_to_vcpu(pmc);

	int idx = pmc->idx;

	u64 period;



	cpu_pmu->pmu.stop(perf_event, PERF_EF_UPDATE);



	/*

	 * Reset the sample period to the architectural limit,

	 * i.e. the point where the counter overflows.

	 */

	period = -(local64_read(&perf_event->count));



	if (!kvm_pmu_idx_is_64bit(vcpu, pmc->idx))

		period &= GENMASK(31, 0);



	local64_set(&perf_event->hw.period_left, 0);

	perf_event->attr.sample_period = period;

	perf_event->hw.sample_period = period;



	__vcpu_sys_reg(vcpu, PMOVSSET_EL0) |= BIT(idx);
@@ -449,6 +469,8 @@ static void kvm_pmu_perf_overflow(struct perf_event *perf_event, 
		kvm_make_request(KVM_REQ_IRQ_PENDING, vcpu);

		kvm_vcpu_kick(vcpu);

	}



	cpu_pmu->pmu.start(perf_event, PERF_EF_RELOAD);

}



/**
@@ -567,12 +589,12 @@ static void kvm_pmu_create_perf_event(struct kvm_vcpu *vcpu, u64 select_idx) 
		 * high counter.

		 */

		attr.sample_period = (-counter) & GENMASK(63, 0);

		if (kvm_pmu_counter_is_enabled(vcpu, pmc->idx + 1))

			attr.config1 |= PERF_ATTR_CFG1_KVM_PMU_CHAINED;



		event = perf_event_create_kernel_counter(&attr, -1, current,

							 kvm_pmu_perf_overflow,

							 pmc + 1);



		if (kvm_pmu_counter_is_enabled(vcpu, pmc->idx + 1))

			attr.config1 |= PERF_ATTR_CFG1_KVM_PMU_CHAINED;

	} else {

		/* The initial sample period (overflow count) of an event. */

		if (kvm_pmu_idx_is_64bit(vcpu, pmc->idx))

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