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Re: [Qemu-devel] [SeaBIOS] [PATCH v3] fw/msr_feature_control: add suppor
From: |
Laszlo Ersek |
Subject: |
Re: [Qemu-devel] [SeaBIOS] [PATCH v3] fw/msr_feature_control: add support to set MSR_IA32_FEATURE_CONTROL |
Date: |
Wed, 6 Jul 2016 08:42:49 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.1.1 |
On 07/06/16 08:28, Haozhong Zhang wrote:
> Hi Ashok,
>
> On 07/06/16 02:18, Paolo Bonzini wrote:
>>> I forgot to restore MSR_IA32_FEATURE_CONTROL in the resume path, and
>>> MSR_IA32_FEATURE_CONTROL is zero after S3 resume.
>>
>> This is a bug. Sorry Laszlo. :)
>>
>>> Not restore MSR_IA32_FEATURE_CONTROL during S3 resume does not affect
>>> at least Linux guest (tested 4.5). Current QEMU may advise the guest
>>> firmware to set bit 20 (for LMCE), bit 2 (for VMX) and bit 0 (lock
>>> bit).
>>> - For LMCE, Linux only checks bit 20 and bit 0 at boot time and then
>>> keeps using the result even after resume.
>>
>> On real hardware, LMCE would not be enabled after resume. I'm not
>> sure what would happen, but it wouldn't be good.
>
> Could you help to check if the LMCE bit in MSR_IA32_FEATURE_CONTROL is
> set after S3 resume on the real hardware?
The SDM says that IA32_FEATURE_CONTROL is zeroed on logical processor reset.
23.7 ENABLING AND ENTERING VMX OPERATION
[...] VMXON is also controlled by the IA32_FEATURE_CONTROL MSR (MSR
address 3AH). This MSR is cleared to zero when a logical processor is
reset. [...]
Thanks
Laszlo
- Re: [Qemu-devel] [SeaBIOS] [PATCH v3] fw/msr_feature_control: add support to set MSR_IA32_FEATURE_CONTROL, Gerd Hoffmann, 2016/07/01
- Re: [Qemu-devel] [SeaBIOS] [PATCH v3] fw/msr_feature_control: add support to set MSR_IA32_FEATURE_CONTROL, Laszlo Ersek, 2016/07/05
- Re: [Qemu-devel] [SeaBIOS] [PATCH v3] fw/msr_feature_control: add support to set MSR_IA32_FEATURE_CONTROL, Haozhong Zhang, 2016/07/05
- Re: [Qemu-devel] [SeaBIOS] [PATCH v3] fw/msr_feature_control: add support to set MSR_IA32_FEATURE_CONTROL, Paolo Bonzini, 2016/07/06
- Re: [Qemu-devel] [SeaBIOS] [PATCH v3] fw/msr_feature_control: add support to set MSR_IA32_FEATURE_CONTROL, Haozhong Zhang, 2016/07/06
- Re: [Qemu-devel] [SeaBIOS] [PATCH v3] fw/msr_feature_control: add support to set MSR_IA32_FEATURE_CONTROL,
Laszlo Ersek <=
- Re: [Qemu-devel] [SeaBIOS] [PATCH v3] fw/msr_feature_control: add support to set MSR_IA32_FEATURE_CONTROL, Haozhong Zhang, 2016/07/06
- Re: [Qemu-devel] [SeaBIOS] [PATCH v3] fw/msr_feature_control: add support to set MSR_IA32_FEATURE_CONTROL, Laszlo Ersek, 2016/07/06
- Re: [Qemu-devel] [SeaBIOS] [PATCH v3] fw/msr_feature_control: add support to set MSR_IA32_FEATURE_CONTROL, Haozhong Zhang, 2016/07/06
- Re: [Qemu-devel] [SeaBIOS] [PATCH v3] fw/msr_feature_control: add support to set MSR_IA32_FEATURE_CONTROL, Laszlo Ersek, 2016/07/06
- Re: [Qemu-devel] [SeaBIOS] [PATCH v3] fw/msr_feature_control: add support to set MSR_IA32_FEATURE_CONTROL, Laszlo Ersek, 2016/07/06
- Re: [Qemu-devel] [SeaBIOS] [PATCH v3] fw/msr_feature_control: add support to set MSR_IA32_FEATURE_CONTROL, Haozhong Zhang, 2016/07/06
- Re: [Qemu-devel] [SeaBIOS] [PATCH v3] fw/msr_feature_control: add support to set MSR_IA32_FEATURE_CONTROL, Laszlo Ersek, 2016/07/06
- Re: [Qemu-devel] [SeaBIOS] [PATCH v3] fw/msr_feature_control: add support to set MSR_IA32_FEATURE_CONTROL, Laszlo Ersek, 2016/07/06
- Re: [Qemu-devel] [SeaBIOS] [PATCH v3] fw/msr_feature_control: add support to set MSR_IA32_FEATURE_CONTROL, Paolo Bonzini, 2016/07/06
- Re: [Qemu-devel] [SeaBIOS] [PATCH v3] fw/msr_feature_control: add support to set MSR_IA32_FEATURE_CONTROL, Laszlo Ersek, 2016/07/06