From e1cc87206348f36fb78e417b5813f78f672a4aef Mon Sep 17 00:00:00 2001 From: Reiji Watanabe Date: Fri, 20 Oct 2023 21:40:51 +0000 Subject: [PATCH] KVM: selftests: aarch64: vPMU register test for unimplemented counters Add a new test case to the vpmu_counter_access test to check if PMU registers or their bits for unimplemented counters are not accessible or are RAZ, as expected. Signed-off-by: Reiji Watanabe Signed-off-by: Raghavendra Rao Ananta Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20231020214053.2144305-12-rananta@google.com [Oliver: fix issues relating to exception return address] Signed-off-by: Oliver Upton --- .../kvm/aarch64/vpmu_counter_access.c | 82 +++++++++++++++++-- .../selftests/kvm/include/aarch64/processor.h | 1 + 2 files changed, 76 insertions(+), 7 deletions(-) diff --git a/tools/testing/selftests/kvm/aarch64/vpmu_counter_access.c b/tools/testing/selftests/kvm/aarch64/vpmu_counter_access.c index a579286b6f116..8694e89684bfe 100644 --- a/tools/testing/selftests/kvm/aarch64/vpmu_counter_access.c +++ b/tools/testing/selftests/kvm/aarch64/vpmu_counter_access.c @@ -5,8 +5,9 @@ * Copyright (c) 2023 Google LLC. * * This test checks if the guest can see the same number of the PMU event - * counters (PMCR_EL0.N) that userspace sets, and if the guest can access - * those counters. + * counters (PMCR_EL0.N) that userspace sets, if the guest can access + * those counters, and if the guest is prevented from accessing any + * other counters. * This test runs only when KVM_CAP_ARM_PMU_V3 is supported on the host. */ #include @@ -287,25 +288,74 @@ static void test_access_pmc_regs(struct pmc_accessor *acc, int pmc_idx) pmc_idx, PMC_ACC_TO_IDX(acc), read_data, write_data); } +#define INVALID_EC (-1ul) +uint64_t expected_ec = INVALID_EC; + static void guest_sync_handler(struct ex_regs *regs) { uint64_t esr, ec; esr = read_sysreg(esr_el1); ec = (esr >> ESR_EC_SHIFT) & ESR_EC_MASK; - __GUEST_ASSERT(0, "PC: 0x%lx; ESR: 0x%lx; EC: 0x%lx", regs->pc, esr, ec); + + __GUEST_ASSERT(expected_ec == ec, + "PC: 0x%lx; ESR: 0x%lx; EC: 0x%lx; EC expected: 0x%lx", + regs->pc, esr, ec, expected_ec); + + /* skip the trapping instruction */ + regs->pc += 4; + + /* Use INVALID_EC to indicate an exception occurred */ + expected_ec = INVALID_EC; +} + +/* + * Run the given operation that should trigger an exception with the + * given exception class. The exception handler (guest_sync_handler) + * will reset op_end_addr to 0, expected_ec to INVALID_EC, and skip + * the instruction that trapped. + */ +#define TEST_EXCEPTION(ec, ops) \ +({ \ + GUEST_ASSERT(ec != INVALID_EC); \ + WRITE_ONCE(expected_ec, ec); \ + dsb(ish); \ + ops; \ + GUEST_ASSERT(expected_ec == INVALID_EC); \ +}) + +/* + * Tests for reading/writing registers for the unimplemented event counter + * specified by @pmc_idx (>= PMCR_EL0.N). + */ +static void test_access_invalid_pmc_regs(struct pmc_accessor *acc, int pmc_idx) +{ + /* + * Reading/writing the event count/type registers should cause + * an UNDEFINED exception. + */ + TEST_EXCEPTION(ESR_EC_UNKNOWN, acc->read_cntr(pmc_idx)); + TEST_EXCEPTION(ESR_EC_UNKNOWN, acc->write_cntr(pmc_idx, 0)); + TEST_EXCEPTION(ESR_EC_UNKNOWN, acc->read_typer(pmc_idx)); + TEST_EXCEPTION(ESR_EC_UNKNOWN, acc->write_typer(pmc_idx, 0)); + /* + * The bit corresponding to the (unimplemented) counter in + * {PMCNTEN,PMINTEN,PMOVS}{SET,CLR} registers should be RAZ. + */ + test_bitmap_pmu_regs(pmc_idx, 1); + test_bitmap_pmu_regs(pmc_idx, 0); } /* * The guest is configured with PMUv3 with @expected_pmcr_n number of * event counters. * Check if @expected_pmcr_n is consistent with PMCR_EL0.N, and - * if reading/writing PMU registers for implemented counters works - * as expected. + * if reading/writing PMU registers for implemented or unimplemented + * counters works as expected. */ static void guest_code(uint64_t expected_pmcr_n) { - uint64_t pmcr, pmcr_n; + uint64_t pmcr, pmcr_n, unimp_mask; int i, pmc; __GUEST_ASSERT(expected_pmcr_n <= ARMV8_PMU_MAX_GENERAL_COUNTERS, @@ -320,15 +370,33 @@ static void guest_code(uint64_t expected_pmcr_n) "Expected PMCR.N: 0x%lx, PMCR.N: 0x%lx", expected_pmcr_n, pmcr_n); + /* + * Make sure that (RAZ) bits corresponding to unimplemented event + * counters in {PMCNTEN,PMINTEN,PMOVS}{SET,CLR} registers are reset + * to zero. + * (NOTE: bits for implemented event counters are reset to UNKNOWN) + */ + unimp_mask = GENMASK_ULL(ARMV8_PMU_MAX_GENERAL_COUNTERS - 1, pmcr_n); + check_bitmap_pmu_regs(unimp_mask, false); + /* * Tests for reading/writing PMU registers for implemented counters. - * Use each combination of PMEVT{CNTR,TYPER}_EL0 accessor functions. + * Use each combination of PMEV{CNTR,TYPER}_EL0 accessor functions. */ for (i = 0; i < ARRAY_SIZE(pmc_accessors); i++) { for (pmc = 0; pmc < pmcr_n; pmc++) test_access_pmc_regs(&pmc_accessors[i], pmc); } + /* + * Tests for reading/writing PMU registers for unimplemented counters. + * Use each combination of PMEV{CNTR,TYPER}_EL0 accessor functions. + */ + for (i = 0; i < ARRAY_SIZE(pmc_accessors); i++) { + for (pmc = pmcr_n; pmc < ARMV8_PMU_MAX_GENERAL_COUNTERS; pmc++) + test_access_invalid_pmc_regs(&pmc_accessors[i], pmc); + } + GUEST_DONE(); } diff --git a/tools/testing/selftests/kvm/include/aarch64/processor.h b/tools/testing/selftests/kvm/include/aarch64/processor.h index cb537253a6b9c..c42d683102c7a 100644 --- a/tools/testing/selftests/kvm/include/aarch64/processor.h +++ b/tools/testing/selftests/kvm/include/aarch64/processor.h @@ -104,6 +104,7 @@ enum { #define ESR_EC_SHIFT 26 #define ESR_EC_MASK (ESR_EC_NUM - 1) +#define ESR_EC_UNKNOWN 0x0 #define ESR_EC_SVC64 0x15 #define ESR_EC_IABT 0x21 #define ESR_EC_DABT 0x25 -- 2.30.2