Messages in this thread | | | Subject | Re: [PATCH 1/1] drivers/hv: correct tsc page sequence invalid value | From | "Denis V. Lunev" <> | Date | Thu, 12 Nov 2015 10:16:19 +0300 |
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On 11/02/2015 10:42 PM, KY Srinivasan wrote: > >> -----Original Message----- >> From: Denis V. Lunev [mailto:den@openvz.org] >> Sent: Monday, November 2, 2015 3:34 AM >> Cc: rkagan@virtuozzo.com; devel@linuxdriverproject.org; linux- >> kernel@vger.kernel.org; Andrey Smetanin <asmetanin@virtuozzo.com>; KY >> Srinivasan <kys@microsoft.com>; Haiyang Zhang >> <haiyangz@microsoft.com>; Vitaly Kuznetsov <vkuznets@redhat.com>; >> Denis V. Lunev <den@openvz.org> >> Subject: [PATCH 1/1] drivers/hv: correct tsc page sequence invalid value >> >> From: Andrey Smetanin <asmetanin@virtuozzo.com> >> >> 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 that Tsc page no longer valid.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@virtuozzo.com> >> CC: "K. Y. Srinivasan" <kys@microsoft.com> > Thanks Andrey; the Hyper-V team will be updating the Hyper-V documentation. > > Acked-by: K. Y. Srinivasan <kys@microsoft.com> > > 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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