Re: [Xen-devel] [PATCH v2] vvmx: fixes after CR4 trapping optimizations

[Sergey Dyasli <sergey.dyasli@xxxxxxxxxx>]

On Fri, 2018-03-02 at 16:19 +0000, Roger Pau Monne wrote:
> Commit 406817 doesn't update nested VMX code in order to take into
> account L1 CR4 host mask when nested guest (L2) writes to CR4, and
> thus the mask written to CR4_GUEST_HOST_MASK is likely not as
> restrictive as it should be.
> 
> Also the VVMCS GUEST_CR4 value should be updated to match the
> underlying value when syncing the VVMCS state.
> 
> Fixes: 406817 ("vmx/hap: optimize CR4 trapping")
> Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
> ---
> Cc: Jun Nakajima <jun.nakajima@xxxxxxxxx>
> Cc: Kevin Tian <kevin.tian@xxxxxxxxx>
> Cc: Jan Beulich <jbeulich@xxxxxxxx>
> Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
> Cc: Sergey Dyasli <sergey.dyasli@xxxxxxxxxx>
> ---
> I've manually tested and AFAICT this fixes the osstest failure
> detected in 120076 ("test-amd64-amd64-qemuu-nested-intel").
> ---
> Changes since v1:
>  - Use guest_cr[4] in order to update the nested VMCS GUEST_CR4.

Reviewed-by: Sergey Dyasli <sergey.dyasli@xxxxxxxxxx>

-- 
Thanks,
Sergey
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