From: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
Add reset handler which gets host value of PMCR_EL0 and make writable
bits architecturally UNKNOWN except PMCR.E which is zero. Add an access
handler for PMCR.
Signed-off-by: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
Reviewed-by: Andrew Jones <drjones@xxxxxxxxxx>
---
arch/arm64/include/asm/kvm_host.h | 3 +++
arch/arm64/kvm/sys_regs.c | 42 +++++++++++++++++++++++++++++++++++++--
include/kvm/arm_pmu.h | 4 ++++
3 files changed, 47 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 6f0241f..1f3ca98 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -115,6 +115,9 @@ enum vcpu_sysreg {
MDSCR_EL1, /* Monitor Debug System Control Register */
MDCCINT_EL1, /* Monitor Debug Comms Channel Interrupt Enable Reg */
+ /* Performance Monitors Registers */
+ PMCR_EL0, /* Control Register */
+
/* 32bit specific registers. Keep them at the end of the range */
DACR32_EL2, /* Domain Access Control Register */
IFSR32_EL2, /* Instruction Fault Status Register */
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 2e90371..e88ae2d 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -34,6 +34,7 @@
#include <asm/kvm_emulate.h>
#include <asm/kvm_host.h>
#include <asm/kvm_mmu.h>
+#include <asm/perf_event.h>
#include <trace/events/kvm.h>
@@ -439,6 +440,43 @@ static void reset_mpidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
vcpu_sys_reg(vcpu, MPIDR_EL1) = (1ULL << 31) | mpidr;
}
+static void reset_pmcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
+{
+ u64 pmcr, val;
+
+ asm volatile("mrs %0, pmcr_el0\n" : "=r" (pmcr));
+ /* Writable bits of PMCR_EL0 (ARMV8_PMU_PMCR_MASK) is reset to UNKNOWN
+ * except PMCR.E resetting to zero.
+ */
+ val = ((pmcr & ~ARMV8_PMU_PMCR_MASK)
+ | (ARMV8_PMU_PMCR_MASK & 0xdecafbad)) & (~ARMV8_PMU_PMCR_E);
+ vcpu_sys_reg(vcpu, PMCR_EL0) = val;
+}
+
+static bool access_pmcr(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
+ const struct sys_reg_desc *r)
+{
+ u64 val;
+
+ if (!kvm_arm_pmu_v3_ready(vcpu))
+ return trap_raz_wi(vcpu, p, r);
+
+ if (p->is_write) {
+ /* Only update writeable bits of PMCR */
+ val = vcpu_sys_reg(vcpu, PMCR_EL0);
+ val &= ~ARMV8_PMU_PMCR_MASK;
+ val |= p->regval & ARMV8_PMU_PMCR_MASK;
+ vcpu_sys_reg(vcpu, PMCR_EL0) = val;
+ } else {
+ /* PMCR.P & PMCR.C are RAZ */
+ val = vcpu_sys_reg(vcpu, PMCR_EL0)
+ & ~(ARMV8_PMU_PMCR_P | ARMV8_PMU_PMCR_C);
+ p->regval = val;
+ }
+
+ 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 */ \
@@ -623,7 +661,7 @@ static const struct sys_reg_desc sys_reg_descs[] = {
/* PMCR_EL0 */
{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1100), Op2(0b000),
- trap_raz_wi },
+ access_pmcr, reset_pmcr, },
/* PMCNTENSET_EL0 */
{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1100), Op2(0b001),
trap_raz_wi },
@@ -885,7 +923,7 @@ static const struct sys_reg_desc cp15_regs[] = {
{ Op1( 0), CRn( 7), CRm(14), Op2( 2), access_dcsw },
/* PMU */
- { Op1( 0), CRn( 9), CRm(12), Op2( 0), trap_raz_wi },
+ { 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( 3), trap_raz_wi },
diff --git a/include/kvm/arm_pmu.h b/include/kvm/arm_pmu.h
index 3c2fd56..8157fe5 100644
--- a/include/kvm/arm_pmu.h
+++ b/include/kvm/arm_pmu.h
@@ -34,9 +34,13 @@ struct kvm_pmu {
struct kvm_pmc pmc[ARMV8_PMU_MAX_COUNTERS];
bool ready;
};
+
+#define kvm_arm_pmu_v3_ready(v) ((v)->arch.pmu.ready)
#else
struct kvm_pmu {
};
+
+#define kvm_arm_pmu_v3_ready(v) (false)
#endif
#endif
--
2.0.4
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