Re: [PATCH 1/1] drivers/hv: correct tsc page sequence invalid value

[Denis V. Lunev]

On 11/02/2015 10:42 PM, KY Srinivasan wrote:
> > -----Original Message-----
> > From: Denis V. Lunev [mailto:den@xxxxxxxxxx]
> > Sent: Monday, November 2, 2015 3:34 AM
> > Cc: rkagan@xxxxxxxxxxxxx; devel@xxxxxxxxxxxxxxxxxxxxxx; linux-
> > kernel@xxxxxxxxxxxxxxx; Andrey Smetanin <asmetanin@xxxxxxxxxxxxx>; KY
> > Srinivasan <kys@xxxxxxxxxxxxx>; Haiyang Zhang
> > <haiyangz@xxxxxxxxxxxxx>; Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>;
> > Denis V. Lunev <den@xxxxxxxxxx>
> > Subject: [PATCH 1/1] drivers/hv: correct tsc page sequence invalid value
> >
> > From: Andrey Smetanin <asmetanin@xxxxxxxxxxxxx>
> >
> > Hypervisor Top Level Functional Specification v3/4 says
> > that TSC page sequence value = -1(0xFFFFFFFF) is used to
> > indicate that TSC page no longer reliable source of reference
> > timer. Unfortunately, we found that Windows Hyper-V guest
> > side implementation uses sequence value = 0 to indicate
> > that Tsc page no longer valid. This is clearly visible
> > inside Windows 2012R2 ntoskrnl.exe HvlGetReferenceTime()
> > function dissassembly:
> >
> > HvlGetReferenceTime proc near
> >                   xchg    ax, ax
> > loc_1401C3132:
> >                   mov     rax, cs:HvlpReferenceTscPage
> >                   mov     r9d, [rax]
> >                   test    r9d, r9d
> >                   jz      short loc_1401C3176
> >                   rdtsc
> >                   mov     rcx, cs:HvlpReferenceTscPage
> >                   shl     rdx, 20h
> >                   or      rdx, rax
> >                   mov     rax, [rcx+8]
> >                   mov     rcx, cs:HvlpReferenceTscPage
> >                   mov     r8, [rcx+10h]
> >                   mul     rdx
> >                   mov     rax, cs:HvlpReferenceTscPage
> >                   add     rdx, r8
> >                   mov     ecx, [rax]
> >                   cmp     ecx, r9d
> >                   jnz     short loc_1401C3132
> >                   jmp     short loc_1401C3184
> > loc_1401C3176:
> >                   mov     ecx, 40000020h
> >                   rdmsr
> >                   shl     rdx, 20h
> >                   or      rdx, rax
> > loc_1401C3184:
> >                   mov     rax, rdx
> >                   retn
> > HvlGetReferenceTime endp
> >
> > This patch aligns Tsc page invalid sequence value with
> > Windows Hyper-V guest implementation which is more
> > compatible with both Hyper-V hypervisor and KVM hypervisor.
> >
> > Signed-off-by: Andrey Smetanin <asmetanin@xxxxxxxxxxxxx>
> > CC: "K. Y. Srinivasan" <kys@xxxxxxxxxxxxx>
> Thanks Andrey; the Hyper-V team will be updating the Hyper-V documentation.
>
> Acked-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx>
>
> Regards,
>
> K. Y
K.Y.,

can you pls clarify the state of this patch? It is a bit unclear
to me whether it is applied or not.

By the way, I also do not see the following patch
"drivers/hv: cleanup synic msrs if vmbus connect failed"
as applied in the Linux-next. You have promised to resend
it will correct author.

Thank you in advance,
    Den
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