Re: [PATCH v3 3/8] x86/msr: explicitly handle AMD DE_CFG

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

On 01/09/2020 11:54, Roger Pau Monne wrote:
> @@ -517,6 +523,15 @@ int guest_wrmsr(struct vcpu *v, uint32_t msr, uint64_t 
> val)
>              wrmsr_tsc_aux(val);
>          break;
>  
> +    case MSR_AMD64_DE_CFG:
> +        /*
> +         * OpenBSD 6.7 will panic if writing to DE_CFG triggers a #GP:
> +         * https://www.illumos.org/issues/12998

"Drop writes", or some suitable equivalent, so it is clear what action
Xen is trying to take in response to the bug.

Otherwise, Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>

> +         */
> +        if ( !(cp->x86_vendor & (X86_VENDOR_AMD | X86_VENDOR_HYGON)) )
> +            goto gp_fault;
> +        break;
> +
>      case MSR_AMD64_DR0_ADDRESS_MASK:
>      case MSR_AMD64_DR1_ADDRESS_MASK ... MSR_AMD64_DR3_ADDRESS_MASK:
>          if ( !cp->extd.dbext || val != (uint32_t)val )