Re: [Qemu-devel] [Qemu-arm] [PATCH v10 10/14] target/arm: Finish implementation of PM[X]EVCNTR and PM[X]EVTYPER

[Aaron Lindsay OS <aaron@os.amperecomputing.com>]

On Feb 04 20:22, Laurent Desnogues wrote:
> Hello,
> 
> On Tue, Dec 11, 2018 at 4:25 PM Aaron Lindsay
> <aaron@os.amperecomputing.com> wrote:
> >
> > Add arrays to hold the registers, the definitions themselves, access
> > functions, and logic to reset counters when PMCR.P is set. Update
> > filtering code to support counters other than PMCCNTR. Support migration
> > with raw read/write functions.
> >
> > Signed-off-by: Aaron Lindsay <alindsay@codeaurora.org>
> > Signed-off-by: Aaron Lindsay <aaron@os.amperecomputing.com>
> > Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
> > ---
> >  target/arm/cpu.h    |   3 +
> >  target/arm/helper.c | 296 +++++++++++++++++++++++++++++++++++++++++---
> >  2 files changed, 282 insertions(+), 17 deletions(-)
> [...]
> > diff --git a/target/arm/helper.c b/target/arm/helper.c
> > index fd2923f033..1b851d1689 100644
> > --- a/target/arm/helper.c
> > +++ b/target/arm/helper.c
> [...]
> > @@ -5301,6 +5526,43 @@ void register_cp_regs_for_features(ARMCPU *cpu)
> >          };
> >          define_one_arm_cp_reg(cpu, &pmcr);
> >          define_one_arm_cp_reg(cpu, &pmcr64);
> > +        for (i = 0; i < pmcrn; i++) {
> > +            char *pmevcntr_name = g_strdup_printf("PMEVCNTR%d", i);
> > +            char *pmevcntr_el0_name = g_strdup_printf("PMEVCNTR%d_EL0", i);
> > +            char *pmevtyper_name = g_strdup_printf("PMEVTYPER%d", i);
> > +            char *pmevtyper_el0_name = g_strdup_printf("PMEVTYPER%d_EL0", i);
> > +            ARMCPRegInfo pmev_regs[] = {
> > +                { .name = pmevcntr_name, .cp = 15, .crn = 15,
> > +                  .crm = 8 | (3 & (i >> 3)), .opc1 = 0, .opc2 = i & 7,
> > +                  .access = PL0_RW, .type = ARM_CP_IO | ARM_CP_ALIAS,
> > +                  .readfn = pmevcntr_readfn, .writefn = pmevcntr_writefn,
> > +                  .accessfn = pmreg_access },
> > +                { .name = pmevcntr_el0_name, .state = ARM_CP_STATE_AA64,
> > +                  .opc0 = 3, .opc1 = 3, .crn = 15, .crm = 8 | (3 & (i >> 3)),
> > +                  .opc2 = i & 7, .access = PL0_RW, .accessfn = pmreg_access,
> > +                  .type = ARM_CP_IO,
> > +                  .readfn = pmevcntr_readfn, .writefn = pmevcntr_writefn,
> > +                  .raw_readfn = pmevcntr_rawread,
> > +                  .raw_writefn = pmevcntr_rawwrite },
> > +                { .name = pmevtyper_name, .cp = 15, .crn = 15,
> > +                  .crm = 12 | (3 & (i >> 3)), .opc1 = 0, .opc2 = i & 7,
> > +                  .access = PL0_RW, .type = ARM_CP_IO | ARM_CP_ALIAS,
> > +                  .readfn = pmevtyper_readfn, .writefn = pmevtyper_writefn,
> > +                  .accessfn = pmreg_access },
> > +                { .name = pmevtyper_el0_name, .state = ARM_CP_STATE_AA64,
> > +                  .opc0 = 3, .opc1 = 3, .crn = 15, .crm = 12 | (3 & (i >> 3)),
> 
> Looking at ARM documentation, I think the value for crn should be 14
> for PMEVCNTR<n>_EL0 and PMEVTYPER<n>_EL0.

You are correct. I'll post a fix momentarily.

Out of curiosity, how did you discover this? I've been using recent
Linux kernels for testing, and thought it used these registers, but I
guess it must only be using PMSELR/PMXEVCNTR/PMXEVTYPER.

-Aaron