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Re: [Qemu-devel] [PATCH] i386: Disable Intel PT if packets IP payloads h
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From: |
Eduardo Habkost |
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Subject: |
Re: [Qemu-devel] [PATCH] i386: Disable Intel PT if packets IP payloads have LIP values |
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Date: |
Wed, 14 Mar 2018 10:02:38 -0300 |
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User-agent: |
Mutt/1.9.2 (2017-12-15) |
On Wed, Mar 14, 2018 at 03:26:31AM +0800, Luwei Kang wrote:
> Intel processor trace should be disabled when
> CPUID.(EAX=14H,ECX=0H).ECX.[bit31] is set.
> Generated packets which contain IP payloads will have LIP
> values when this bit is set, or IP payloads will have RIP
> values.
> Currently, The information of CPUID 14H is constant to make
> live migration safty and this bit is always 0 in guest even
> if host support LIP values.
> Guest sees the bit is 0 will expect IP payloads with RIP
> values, but the host CPU will generate IP payloads with
> LIP values if this bit is set in HW.
> To make sure the value of IP payloads correctly, Intel PT
> should be disabled when bit[31] is set.
>
> Signed-off-by: Luwei Kang <address@hidden>
Queued, thanks.
--
Eduardo