Re: [PATCH v3 15/16] hw/i386/vmport: Add support for CMD_GETHZ

[Philippe Mathieu-Daudé]

On 3/12/20 5:54 PM, Liran Alon wrote:
> This command returns to guest information on LAPIC bus frequency and TSC
> frequency.
>
> One can see how this interface is used by Linux vmware_platform_setup()
> introduced in Linux commit 88b094fb8d4f ("x86: Hypervisor detection and
> get tsc_freq from hypervisor").
>
> Reviewed-by: Nikita Leshenko <address@hidden>
> Signed-off-by: Liran Alon <address@hidden>
> ---
>   hw/i386/vmport.c         | 19 +++++++++++++++++++
>   include/hw/i386/vmport.h |  1 +
>   2 files changed, 20 insertions(+)
>
> diff --git a/hw/i386/vmport.c b/hw/i386/vmport.c
> index 1664a6b97332..9d3921cf418d 100644
> --- a/hw/i386/vmport.c
> +++ b/hw/i386/vmport.c
> @@ -176,6 +176,24 @@ static uint32_t vmport_cmd_ram_size(void *opaque, uint32_t 
> addr)
>       return ram_size;
>   }
>   
> +static uint32_t vmport_cmd_get_hz(void *opaque, uint32_t addr)
> +{
> +    X86CPU *cpu = X86_CPU(current_cpu);
> +
> +    if (cpu->env.tsc_khz && cpu->env.apic_bus_freq) {
> +        uint64_t tsc_freq = (uint64_t)cpu->env.tsc_khz * 1000;
> +
> +        cpu->env.regs[R_ECX] = cpu->env.apic_bus_freq;
> +        cpu->env.regs[R_EBX] = (uint32_t)(tsc_freq >> 32);
> +        cpu->env.regs[R_EAX] = (uint32_t)tsc_freq;
> +    } else {
> +        /* Signal cmd as not supported */
> +        cpu->env.regs[R_EBX] = UINT32_MAX;
> +    }
> +
> +    return cpu->env.regs[R_EAX];
> +}
> +
>   static uint32_t vmport_cmd_time(void *opaque, uint32_t addr)
>   {
>       X86CPU *cpu = X86_CPU(current_cpu);
> @@ -265,6 +283,7 @@ static void vmport_realizefn(DeviceState *dev, Error **errp)
>       if (s->compat_flags & VMPORT_COMPAT_CMDS_V2) {
>           vmport_register(VMPORT_CMD_GETBIOSUUID, vmport_cmd_get_bios_uuid, 
> NULL);
>           vmport_register(VMPORT_CMD_GETTIME, vmport_cmd_time, NULL);
> +        vmport_register(VMPORT_CMD_GETHZ, vmport_cmd_get_hz, NULL);
>           vmport_register(VMPORT_CMD_GETTIMEFULL, vmport_cmd_time_full, NULL);
>           vmport_register(VMPORT_CMD_GET_VCPU_INFO, vmport_cmd_get_vcpu_info,
>                           NULL);
> diff --git a/include/hw/i386/vmport.h b/include/hw/i386/vmport.h
> index 34cc050b1ffa..aee809521aa0 100644
> --- a/include/hw/i386/vmport.h
> +++ b/include/hw/i386/vmport.h
> @@ -12,6 +12,7 @@ typedef enum {
>       VMPORT_CMD_VMMOUSE_DATA     = 39,
>       VMPORT_CMD_VMMOUSE_STATUS   = 40,
>       VMPORT_CMD_VMMOUSE_COMMAND  = 41,
> +    VMPORT_CMD_GETHZ            = 45,

Can you rename to something easier to read, such _GET_FREQS_HZ or nicer?

>       VMPORT_CMD_GETTIMEFULL      = 46,
>       VMPORT_CMD_GET_VCPU_INFO    = 68,
>       VMPORT_ENTRIES