[PATCH v7 12/12] KVM: selftests: aarch64: vPMU register test for unimplemented counters
Raghavendra Rao Ananta
rananta at google.com
Thu Oct 19 11:09:13 PDT 2023
On Tue, Oct 17, 2023 at 11:54 PM Eric Auger <eauger at redhat.com> wrote:
>
> Hi Raghavendra,
>
> On 10/10/23 01:08, Raghavendra Rao Ananta wrote:
> > From: Reiji Watanabe <reijiw at google.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 at google.com>
> > Signed-off-by: Raghavendra Rao Ananta <rananta at google.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
>
Thanks for the comments, Eric. I'll fix these.
- Raghavendra
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