Re: [PATCH v2] target/i386/hvf: add vmware-cpuid-freq cpu feature

[Vladislav Yaroshchuk <yaroshchuk2000@gmail.com>]

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Hi Cameron,

ср, 20 янв. 2021 г. в 01:37, Cameron Esfahani <dirty@apple.com>:

>
>
> > On Jan 14, 2021, at 11:47 AM, yaroshchuk2000@gmail.com wrote:
> >
> > From: Vladislav Yaroshchuk <yaroshchuk2000@gmail.com>
> >
> > For `-accel hvf` cpu_x86_cpuid() is wrapped with hvf_cpu_x86_cpuid() to
> > add paravirtualization cpuid leaf 0x40000010
> > https://lkml.org/lkml/2008/10/1/246
> >
> > Leaf 0x40000010, Timing Information:
> > EAX: (Virtual) TSC frequency in kHz.
> > EBX: (Virtual) Bus (local apic timer) frequency in kHz.
> > ECX, EDX: RESERVED (Per above, reserved fields are set to zero).
> >
> > On macOS TSC and APIC Bus frequencies can be readed by sysctl call with
> > names `machdep.tsc.frequency` and `hw.busfrequency`
> >
> > This options is required for Darwin-XNU guest to be synchronized with
> > host
> >
> > Signed-off-by: Vladislav Yaroshchuk <yaroshchuk2000@gmail.com>
> > ---
> > target/i386/hvf/hvf.c | 90 ++++++++++++++++++++++++++++++++++++++++++-
> > 1 file changed, 89 insertions(+), 1 deletion(-)
> >
> > diff --git a/target/i386/hvf/hvf.c b/target/i386/hvf/hvf.c
> > index ed9356565c..a5daafe202 100644
> > --- a/target/i386/hvf/hvf.c
> > +++ b/target/i386/hvf/hvf.c
> > @@ -65,6 +65,7 @@
> >
> > #include <Hypervisor/hv.h>
> > #include <Hypervisor/hv_vmx.h>
> > +#include <sys/sysctl.h>
> >
> > #include "exec/address-spaces.h"
> > #include "hw/i386/apic_internal.h"
> > @@ -456,6 +457,48 @@ static void dummy_signal(int sig)
> > {
> > }
> >
> > +static void init_tsc_freq(CPUX86State *env)
> > +{
> > +    size_t length;
> > +    uint64_t tsc_freq;
> > +
> > +    if (env->tsc_khz != 0) {
> > +        return;
> > +    }
> > +
> > +    length = sizeof(uint64_t);
> > +    if (sysctlbyname("machdep.tsc.frequency", &tsc_freq, &length, NULL,
> 0)) {
> > +        return;
> > +    }
> > +    env->tsc_khz = tsc_freq / 1000;  /* Hz to KHz */
> > +}
> > +
> > +static void init_apic_bus_freq(CPUX86State *env)
> > +{
> > +    size_t length;
> > +    uint64_t bus_freq;
> > +
> > +    if (env->apic_bus_freq != 0) {
> > +        return;
> > +    }
> > +
> > +    length = sizeof(uint64_t);
> > +    if (sysctlbyname("hw.busfrequency", &bus_freq, &length, NULL, 0)) {
> > +        return;
> > +    }
> > +    env->apic_bus_freq = bus_freq;
> > +}
> > +
> > +static inline bool tsc_is_known(CPUX86State *env)
> > +{
> > +    return env->tsc_khz != 0;
> > +}
> > +
> > +static inline bool apic_bus_freq_is_known(CPUX86State *env)
> > +{
> > +    return env->apic_bus_freq != 0;
> > +}
> > +
> > int hvf_init_vcpu(CPUState *cpu)
> > {
> >
> > @@ -480,6 +523,15 @@ int hvf_init_vcpu(CPUState *cpu)
> >     hvf_state->hvf_caps = g_new0(struct hvf_vcpu_caps, 1);
> >     env->hvf_mmio_buf = g_new(char, 4096);
> >
> > +    if (x86cpu->vmware_cpuid_freq) {
> > +        init_tsc_freq(env);
> > +        init_apic_bus_freq(env);
> > +
> > +        if (!tsc_is_known(env) || !apic_bus_freq_is_known(env)) {
> > +            error_report("vmware-cpuid-freq: feature couldn't be
> enabled");
> > +        }
> > +    }
> > +
> >     r = hv_vcpu_create((hv_vcpuid_t *)&cpu->hvf_fd, HV_VCPU_DEFAULT);
> >     cpu->vcpu_dirty = 1;
> >     assert_hvf_ok(r);
> > @@ -597,6 +649,42 @@ static void hvf_store_events(CPUState *cpu,
> uint32_t ins_len, uint64_t idtvec_in
> >     }
> > }
> >
>
> Seems that

> We already have hvf/x86_cpuid.c.  Can we put hvf_cpu_x86_cpuid() in there?
>
> hvf/x86_cpuid.c is about host features, hvf_cpu_x86_cpuid() does not fit
it, as for me.
Also, KVM extends cpuid in target/i386/kvm/kvm.c. Same to WHPX:
target/i386/whpx/whpx-all.c.
I wanted to meet this rule: target/i386/hvf/hvf.c

Thank you!

Vladislav Yaroshchuk

> +static void hvf_cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t
> count,
> > +                              uint32_t *eax, uint32_t *ebx,
> > +                              uint32_t *ecx, uint32_t *edx)
> > +{
> > +    /*
> > +     * A wrapper extends cpu_x86_cpuid with 0x40000000 and 0x40000010
> leafs
> > +     * Provides vmware-cpuid-freq support to hvf
> > +     */
> > +
> > +    uint32_t signature[3];
> > +
> > +    if (!tsc_is_known(env) || !apic_bus_freq_is_known(env)) {
> > +        cpu_x86_cpuid(env, index, count, eax, ebx, ecx, edx);
> > +        return;
> > +    }
> > +
> > +    switch (index) {
> > +    case 0x40000000:
> > +        memcpy(signature, "TCGTCGTCGTCG", 12); /* QEMU Signature */
>
> I agree with Roman, using "HVFHVFHVFHVF" is better.
>
> > +        *eax = 0x40000010;                     /* Max available cpuid
> leaf */
> > +        *ebx = signature[0];
> > +        *ecx = signature[1];
> > +        *edx = signature[2];
> > +        break;
> > +    case 0x40000010:
> > +        *eax = env->tsc_khz;
> > +        *ebx = env->apic_bus_freq / 1000; /* Hz to KHz */
> > +        *ecx = 0;
> > +        *edx = 0;
> > +        break;
> > +    default:
> > +        cpu_x86_cpuid(env, index, count, eax, ebx, ecx, edx);
> > +        break;
> > +    }
> > +}
> > +
> > int hvf_vcpu_exec(CPUState *cpu)
> > {
> >     X86CPU *x86_cpu = X86_CPU(cpu);
> > @@ -734,7 +822,7 @@ int hvf_vcpu_exec(CPUState *cpu)
> >             uint32_t rcx = (uint32_t)rreg(cpu->hvf_fd, HV_X86_RCX);
> >             uint32_t rdx = (uint32_t)rreg(cpu->hvf_fd, HV_X86_RDX);
> >
> > -            cpu_x86_cpuid(env, rax, rcx, &rax, &rbx, &rcx, &rdx);
> > +            hvf_cpu_x86_cpuid(env, rax, rcx, &rax, &rbx, &rcx, &rdx);
> >
> >             wreg(cpu->hvf_fd, HV_X86_RAX, rax);
> >             wreg(cpu->hvf_fd, HV_X86_RBX, rbx);
> > --
> > 2.28.0
> >
> >
>
> Looks good.
>
> Cameron Esfahani
> dirty@apple.com
>
>

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