From fe0c88919cf28ab6f30986da07e87f59e4590a88 Mon Sep 17 00:00:00 2001 From: Jean-Philippe Brucker Date: Tue, 19 Dec 2023 17:57:50 +0000 Subject: [PATCH] target/arm/helper: Propagate MDCR_EL2.HPMN into PMCR_EL0.N MDCR_EL2.HPMN allows an hypervisor to limit the number of PMU counters available to EL1 and EL0 (to keep the others to itself). QEMU already implements this split correctly, except for PMCR_EL0.N reads: the number of counters read by EL1 or EL0 should be the one configured in MDCR_EL2.HPMN. Cc: qemu-stable@nongnu.org Signed-off-by: Jean-Philippe Brucker Message-id: 20231215144652.4193815-2-jean-philippe@linaro.org Reviewed-by: Peter Maydell Signed-off-by: Peter Maydell (cherry picked from commit 6980c31dec42b6daebf7fec13b2d39ed87bb4766) Signed-off-by: Michael Tokarev --- target/arm/helper.c | 22 ++++++++++++++++++++-- 1 file changed, 20 insertions(+), 2 deletions(-) diff --git a/target/arm/helper.c b/target/arm/helper.c index a52ef3dfe4..02cfeece45 100644 --- a/target/arm/helper.c +++ b/target/arm/helper.c @@ -1431,6 +1431,22 @@ static void pmcr_write(CPUARMState *env, const ARMCPRegInfo *ri, pmu_op_finish(env); } +static uint64_t pmcr_read(CPUARMState *env, const ARMCPRegInfo *ri) +{ + uint64_t pmcr = env->cp15.c9_pmcr; + + /* + * If EL2 is implemented and enabled for the current security state, reads + * of PMCR.N from EL1 or EL0 return the value of MDCR_EL2.HPMN or HDCR.HPMN. + */ + if (arm_current_el(env) <= 1 && arm_is_el2_enabled(env)) { + pmcr &= ~PMCRN_MASK; + pmcr |= (env->cp15.mdcr_el2 & MDCR_HPMN) << PMCRN_SHIFT; + } + + return pmcr; +} + static void pmswinc_write(CPUARMState *env, const ARMCPRegInfo *ri, uint64_t value) { @@ -6499,8 +6515,9 @@ static void define_pmu_regs(ARMCPU *cpu) .access = PL0_RW, .type = ARM_CP_IO | ARM_CP_ALIAS, .fieldoffset = offsetoflow32(CPUARMState, cp15.c9_pmcr), - .accessfn = pmreg_access, .writefn = pmcr_write, - .raw_writefn = raw_write, + .accessfn = pmreg_access, + .readfn = pmcr_read, .raw_readfn = raw_read, + .writefn = pmcr_write, .raw_writefn = raw_write, }; ARMCPRegInfo pmcr64 = { .name = "PMCR_EL0", .state = ARM_CP_STATE_AA64, @@ -6509,6 +6526,7 @@ static void define_pmu_regs(ARMCPU *cpu) .type = ARM_CP_IO, .fieldoffset = offsetof(CPUARMState, cp15.c9_pmcr), .resetvalue = cpu->isar.reset_pmcr_el0, + .readfn = pmcr_read, .raw_readfn = raw_read, .writefn = pmcr_write, .raw_writefn = raw_write, };