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LoongArch: KVM: Add PMU support for guest

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On LoongArch, the host and guest have their own PMU CSRs registers and
they share PMU hardware resources. A set of PMU CSRs consists of a CTRL
register and a CNTR register. We can set which PMU CSRs are used by the
guest by writing to the GCFG register [24:26] bits.

On KVM side:
- Save the host PMU CSRs into structure kvm_context.
- If the host supports the PMU feature.
  - When entering guest mode, save the host PMU CSRs and restore the guest PMU CSRs.
  - When exiting guest mode, save the guest PMU CSRs and restore the host PMU CSRs.

Reviewed-by: Bibo Mao <maobibo@loongson.cn>
Signed-off-by: Song Gao <gaosong@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
This commit is contained in:
Song Gao
2024-09-12 20:53:40 +08:00
committed by Huacai Chen
parent acc7f20d54
commit f4e40ea9f7
7 changed files with 205 additions and 3 deletions
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165
arch/loongarch/kvm/vcpu.c
View File

@@ -32,6 +32,126 @@ const struct kvm_stats_header kvm_vcpu_stats_header = {
sizeof(kvm_vcpu_stats_desc),
};
static inline void kvm_save_host_pmu(struct kvm_vcpu *vcpu)
{
struct kvm_context *context;
context = this_cpu_ptr(vcpu->kvm->arch.vmcs);
context->perf_cntr[0] = read_csr_perfcntr0();
context->perf_cntr[1] = read_csr_perfcntr1();
context->perf_cntr[2] = read_csr_perfcntr2();
context->perf_cntr[3] = read_csr_perfcntr3();
context->perf_ctrl[0] = write_csr_perfctrl0(0);
context->perf_ctrl[1] = write_csr_perfctrl1(0);
context->perf_ctrl[2] = write_csr_perfctrl2(0);
context->perf_ctrl[3] = write_csr_perfctrl3(0);
}
static inline void kvm_restore_host_pmu(struct kvm_vcpu *vcpu)
{
struct kvm_context *context;
context = this_cpu_ptr(vcpu->kvm->arch.vmcs);
write_csr_perfcntr0(context->perf_cntr[0]);
write_csr_perfcntr1(context->perf_cntr[1]);
write_csr_perfcntr2(context->perf_cntr[2]);
write_csr_perfcntr3(context->perf_cntr[3]);
write_csr_perfctrl0(context->perf_ctrl[0]);
write_csr_perfctrl1(context->perf_ctrl[1]);
write_csr_perfctrl2(context->perf_ctrl[2]);
write_csr_perfctrl3(context->perf_ctrl[3]);
}
static inline void kvm_save_guest_pmu(struct kvm_vcpu *vcpu)
{
struct loongarch_csrs *csr = vcpu->arch.csr;
kvm_save_hw_gcsr(csr, LOONGARCH_CSR_PERFCNTR0);
kvm_save_hw_gcsr(csr, LOONGARCH_CSR_PERFCNTR1);
kvm_save_hw_gcsr(csr, LOONGARCH_CSR_PERFCNTR2);
kvm_save_hw_gcsr(csr, LOONGARCH_CSR_PERFCNTR3);
kvm_read_clear_hw_gcsr(csr, LOONGARCH_CSR_PERFCTRL0);
kvm_read_clear_hw_gcsr(csr, LOONGARCH_CSR_PERFCTRL1);
kvm_read_clear_hw_gcsr(csr, LOONGARCH_CSR_PERFCTRL2);
kvm_read_clear_hw_gcsr(csr, LOONGARCH_CSR_PERFCTRL3);
}
static inline void kvm_restore_guest_pmu(struct kvm_vcpu *vcpu)
{
struct loongarch_csrs *csr = vcpu->arch.csr;
kvm_restore_hw_gcsr(csr, LOONGARCH_CSR_PERFCNTR0);
kvm_restore_hw_gcsr(csr, LOONGARCH_CSR_PERFCNTR1);
kvm_restore_hw_gcsr(csr, LOONGARCH_CSR_PERFCNTR2);
kvm_restore_hw_gcsr(csr, LOONGARCH_CSR_PERFCNTR3);
kvm_restore_hw_gcsr(csr, LOONGARCH_CSR_PERFCTRL0);
kvm_restore_hw_gcsr(csr, LOONGARCH_CSR_PERFCTRL1);
kvm_restore_hw_gcsr(csr, LOONGARCH_CSR_PERFCTRL2);
kvm_restore_hw_gcsr(csr, LOONGARCH_CSR_PERFCTRL3);
}
static int kvm_own_pmu(struct kvm_vcpu *vcpu)
{
unsigned long val;
if (!kvm_guest_has_pmu(&vcpu->arch))
return -EINVAL;
kvm_save_host_pmu(vcpu);
/* Set PM0-PM(num) to guest */
val = read_csr_gcfg() & ~CSR_GCFG_GPERF;
val |= (kvm_get_pmu_num(&vcpu->arch) + 1) << CSR_GCFG_GPERF_SHIFT;
write_csr_gcfg(val);
kvm_restore_guest_pmu(vcpu);
return 0;
}
static void kvm_lose_pmu(struct kvm_vcpu *vcpu)
{
unsigned long val;
struct loongarch_csrs *csr = vcpu->arch.csr;
if (!(vcpu->arch.aux_inuse & KVM_LARCH_PMU))
return;
kvm_save_guest_pmu(vcpu);
/* Disable pmu access from guest */
write_csr_gcfg(read_csr_gcfg() & ~CSR_GCFG_GPERF);
/*
* Clear KVM_LARCH_PMU if the guest is not using PMU CSRs when
* exiting the guest, so that the next time trap into the guest.
* We don't need to deal with PMU CSRs contexts.
*/
val = kvm_read_sw_gcsr(csr, LOONGARCH_CSR_PERFCTRL0);
val |= kvm_read_sw_gcsr(csr, LOONGARCH_CSR_PERFCTRL1);
val |= kvm_read_sw_gcsr(csr, LOONGARCH_CSR_PERFCTRL2);
val |= kvm_read_sw_gcsr(csr, LOONGARCH_CSR_PERFCTRL3);
if (!(val & KVM_PMU_EVENT_ENABLED))
vcpu->arch.aux_inuse &= ~KVM_LARCH_PMU;
kvm_restore_host_pmu(vcpu);
}
static void kvm_restore_pmu(struct kvm_vcpu *vcpu)
{
if ((vcpu->arch.aux_inuse & KVM_LARCH_PMU))
kvm_make_request(KVM_REQ_PMU, vcpu);
}
static void kvm_check_pmu(struct kvm_vcpu *vcpu)
{
if (kvm_check_request(KVM_REQ_PMU, vcpu)) {
kvm_own_pmu(vcpu);
vcpu->arch.aux_inuse |= KVM_LARCH_PMU;
}
}
static void kvm_update_stolen_time(struct kvm_vcpu *vcpu)
{
u32 version;
@@ -159,6 +279,7 @@ static int kvm_pre_enter_guest(struct kvm_vcpu *vcpu)
/* Make sure the vcpu mode has been written */
smp_store_mb(vcpu->mode, IN_GUEST_MODE);
kvm_check_vpid(vcpu);
kvm_check_pmu(vcpu);
/*
* Called after function kvm_check_vpid()
@@ -196,6 +317,8 @@ static int kvm_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu)
/* Set a default exit reason */
run->exit_reason = KVM_EXIT_UNKNOWN;
kvm_lose_pmu(vcpu);
guest_timing_exit_irqoff();
guest_state_exit_irqoff();
local_irq_enable();
@@ -469,6 +592,22 @@ static int _kvm_setcsr(struct kvm_vcpu *vcpu, unsigned int id, u64 val)
kvm_write_sw_gcsr(csr, id, val);
/*
* After modifying the PMU CSR register value of the vcpu.
* If the PMU CSRs are used, we need to set KVM_REQ_PMU.
*/
if (id >= LOONGARCH_CSR_PERFCTRL0 && id <= LOONGARCH_CSR_PERFCNTR3) {
unsigned long val;
val = kvm_read_sw_gcsr(csr, LOONGARCH_CSR_PERFCTRL0) |
kvm_read_sw_gcsr(csr, LOONGARCH_CSR_PERFCTRL1) |
kvm_read_sw_gcsr(csr, LOONGARCH_CSR_PERFCTRL2) |
kvm_read_sw_gcsr(csr, LOONGARCH_CSR_PERFCTRL3);
if (val & KVM_PMU_EVENT_ENABLED)
kvm_make_request(KVM_REQ_PMU, vcpu);
}
return ret;
}
@@ -513,6 +652,12 @@ static int _kvm_get_cpucfg_mask(int id, u64 *v)
case LOONGARCH_CPUCFG5:
*v = GENMASK(31, 0);
return 0;
case LOONGARCH_CPUCFG6:
if (cpu_has_pmp)
*v = GENMASK(14, 0);
else
*v = 0;
return 0;
case LOONGARCH_CPUCFG16:
*v = GENMASK(16, 0);
return 0;
@@ -557,6 +702,17 @@ static int kvm_check_cpucfg(int id, u64 val)
/* LASX architecturally implies LSX and FP but val does not satisfy that */
return -EINVAL;
return 0;
case LOONGARCH_CPUCFG6:
if (val & CPUCFG6_PMP) {
u32 host = read_cpucfg(LOONGARCH_CPUCFG6);
if ((val & CPUCFG6_PMBITS) != (host & CPUCFG6_PMBITS))
return -EINVAL;
if ((val & CPUCFG6_PMNUM) > (host & CPUCFG6_PMNUM))
return -EINVAL;
if ((val & CPUCFG6_UPM) && !(host & CPUCFG6_UPM))
return -EINVAL;
}
return 0;
default:
/*
* Values for the other CPUCFG IDs are not being further validated
@@ -670,6 +826,9 @@ static int kvm_set_one_reg(struct kvm_vcpu *vcpu,
if (ret)
break;
vcpu->arch.cpucfg[id] = (u32)v;
if (id == LOONGARCH_CPUCFG6)
vcpu->arch.max_pmu_csrid =
LOONGARCH_CSR_PERFCTRL0 + 2 * kvm_get_pmu_num(&vcpu->arch) + 1;
break;
case KVM_REG_LOONGARCH_LBT:
if (!kvm_guest_has_lbt(&vcpu->arch))
@@ -791,7 +950,8 @@ static int kvm_loongarch_cpucfg_has_attr(struct kvm_vcpu *vcpu,
struct kvm_device_attr *attr)
{
switch (attr->attr) {
case 2:
case LOONGARCH_CPUCFG2:
case LOONGARCH_CPUCFG6:
return 0;
default:
return -ENXIO;
@@ -1356,6 +1516,9 @@ static int _kvm_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
change_csr_gcfg(CSR_GCFG_MATC_MASK, CSR_GCFG_MATC_ROOT);
kvm_make_request(KVM_REQ_STEAL_UPDATE, vcpu);
/* Restore hardware PMU CSRs */
kvm_restore_pmu(vcpu);
/* Don't bother restoring registers multiple times unless necessary */
if (vcpu->arch.aux_inuse & KVM_LARCH_HWCSR_USABLE)
return 0;