Re: [Xen-devel] [PATCH v2] x86/vmx: Fix vmentry failure because of invalid LER on Broadwell

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

On 30/05/17 15:05, Ross Lagerwall wrote:
> Occasionally, on certain Broadwell CPUs MSR_IA32_LASTINTTOIP has been
> observed to have the top three bits corrupted as though the MSR is using
> the LBR_FORMAT_EIP_FLAGS_TSX format. This is incorrect and causes a
> vmentry failure -- the MSR should contain an offset into the current
> code segment. This is assumed to be erratum BDF14. Workaround the issue
> by sign-extending into bits 48:63 for MSR_IA32_LASTINT{FROM,TO}IP.
>
> Signed-off-by: Ross Lagerwall <ross.lagerwall@xxxxxxxxxx>

Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>, with one minor
issue which can be fixed up on commit.

> @@ -2791,7 +2793,11 @@ enum
>  
>  #define LBR_FROM_SIGNEXT_2MSB  ((1ULL << 59) | (1ULL << 60))
>  
> +#define FIXUP_LBR_TSX            (1 << 0)
> +#define FIXUP_BDW_ERRATUM_BDF14  (1 << 1)

1u <<

~Andrew

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