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Message-ID: <3e6e6c25-7b20-46b4-ffce-d34841aca209@redhat.com>
Date: Wed, 18 Oct 2023 08:54:26 +0200
From: Eric Auger <eauger@...hat.com>
To: Raghavendra Rao Ananta <rananta@...gle.com>,
Oliver Upton <oliver.upton@...ux.dev>,
Marc Zyngier <maz@...nel.org>
Cc: Alexandru Elisei <alexandru.elisei@....com>,
James Morse <james.morse@....com>,
Suzuki K Poulose <suzuki.poulose@....com>,
Paolo Bonzini <pbonzini@...hat.com>,
Zenghui Yu <yuzenghui@...wei.com>,
Shaoqin Huang <shahuang@...hat.com>,
Jing Zhang <jingzhangos@...gle.com>,
Reiji Watanabe <reijiw@...gle.com>,
Colton Lewis <coltonlewis@...gle.com>,
linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.linux.dev,
linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Subject: Re: [PATCH v7 12/12] KVM: selftests: aarch64: vPMU register test for
unimplemented counters
Hi Raghavendra,
On 10/10/23 01:08, Raghavendra Rao Ananta wrote:
> From: Reiji Watanabe <reijiw@...gle.com>
>
> 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 <reijiw@...gle.com>
> Signed-off-by: Raghavendra Rao Ananta <rananta@...gle.com>
> ---
> .../kvm/aarch64/vpmu_counter_access.c | 95 +++++++++++++++++--
> .../selftests/kvm/include/aarch64/processor.h | 1 +
> 2 files changed, 87 insertions(+), 9 deletions(-)
>
> diff --git a/tools/testing/selftests/kvm/aarch64/vpmu_counter_access.c b/tools/testing/selftests/kvm/aarch64/vpmu_counter_access.c
> index e92af3c0db03..788386ac0894 100644
> --- a/tools/testing/selftests/kvm/aarch64/vpmu_counter_access.c
> +++ b/tools/testing/selftests/kvm/aarch64/vpmu_counter_access.c
> @@ -5,8 +5,8 @@
> * Copyright (c) 2022 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 cannot access any other counters.
I would suggest: 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 <kvm_util.h>
> @@ -131,9 +131,9 @@ static void write_pmevtypern(int n, unsigned long val)
> }
>
> /*
> - * The pmc_accessor structure has pointers to PMEVT{CNTR,TYPER}<n>_EL0
> + * The pmc_accessor structure has pointers to PMEV{CNTR,TYPER}<n>_EL0
> * accessors that test cases will use. Each of the accessors will
> - * either directly reads/writes PMEVT{CNTR,TYPER}<n>_EL0
> + * either directly reads/writes PMEV{CNTR,TYPER}<n>_EL0
I guess this should belong to the previous patch?
> * (i.e. {read,write}_pmev{cnt,type}rn()), or reads/writes them through
> * PMXEV{CNTR,TYPER}_EL0 (i.e. {read,write}_sel_ev{cnt,type}r()).
> *
> @@ -291,25 +291,85 @@ 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;
> +uint64_t op_end_addr;
> +
> 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(op_end_addr && (expected_ec == ec),
> + "PC: 0x%lx; ESR: 0x%lx; EC: 0x%lx; EC expected: 0x%lx",
> + regs->pc, esr, ec, expected_ec);
> +
> + /* Will go back to op_end_addr after the handler exits */
> + regs->pc = op_end_addr;
> +
> + /*
> + * Clear op_end_addr, and setting expected_ec to INVALID_EC
and set
> + * as a sign that an exception has occurred.
> + */
> + op_end_addr = 0;
> + 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, and expected_ec to INVALID_EC, and
> + * will come back to the instruction at the @done_label.
> + * The @done_label must be a unique label in this test program.
> + */
> +#define TEST_EXCEPTION(ec, ops, done_label) \
> +{ \
> + extern int done_label; \
> + \
> + WRITE_ONCE(op_end_addr, (uint64_t)&done_label); \
> + GUEST_ASSERT(ec != INVALID_EC); \
> + WRITE_ONCE(expected_ec, ec); \
> + dsb(ish); \
> + ops; \
> + asm volatile(#done_label":"); \
> + GUEST_ASSERT(!op_end_addr); \
> + 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), inv_rd_cntr);
> + TEST_EXCEPTION(ESR_EC_UNKNOWN, acc->write_cntr(pmc_idx, 0), inv_wr_cntr);
> + TEST_EXCEPTION(ESR_EC_UNKNOWN, acc->read_typer(pmc_idx), inv_rd_typer);
> + TEST_EXCEPTION(ESR_EC_UNKNOWN, acc->write_typer(pmc_idx, 0), inv_wr_typer);
> + /*
> + * The bit corresponding to the (unimplemented) counter in
> + * {PMCNTEN,PMOVS}{SET,CLR}_EL1 registers should be RAZ.
{PMCNTEN,PMINTEN,PMOVS}{SET,CLR}
> + */
> + 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 can work
> - * as expected.
> + * if reading/writing PMU registers for implemented or unimplemented
> + * counters can work 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,
> @@ -324,15 +384,32 @@ static void guest_code(uint64_t expected_pmcr_n)
> "Expected PMCR.N: 0x%lx, PMCR.N: 0x%lx",
> pmcr_n, expected_pmcr_n);
>
> + /*
> + * Make sure that (RAZ) bits corresponding to unimplemented event
> + * counters in {PMCNTEN,PMOVS}{SET,CLR}_EL1 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);
wrt above comment, this also checks pmintenset|clr_el1.
> +
> /*
> * Tests for reading/writing PMU registers for implemented counters.
> - * Use each combination of PMEVT{CNTR,TYPER}<n>_EL0 accessor functions.
> + * Use each combination of PMEV{CNTR,TYPER}<n>_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}<n>_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 cb537253a6b9..c42d683102c7 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
Thanks
Eric
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