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[Qemu-devel] Re: [PATCH v3 12/21] kvm: x86: Drop MCE MSRs write back res
From: |
Jan Kiszka |
Subject: |
[Qemu-devel] Re: [PATCH v3 12/21] kvm: x86: Drop MCE MSRs write back restrictions |
Date: |
Wed, 05 Jan 2011 09:07:36 +0100 |
User-agent: |
Mozilla/5.0 (X11; U; Linux i686 (x86_64); de; rv:1.8.1.12) Gecko/20080226 SUSE/2.0.0.12-1.1 Thunderbird/2.0.0.12 Mnenhy/0.7.5.666 |
Am 05.01.2011 07:42, Huang Ying wrote:
> On Tue, 2011-01-04 at 16:32 +0800, Jan Kiszka wrote:
>> From: Jan Kiszka <address@hidden>
>>
>> There is no need to restrict writing back MCE MSRs to reset or full
>> state updates as setting their values has no side effects.
>
> Sorry for late.
Don't worry.
>
> The MCE MSRs contents is sticky for warm reset except MCG_STATUS, so
> their content should be kept. And the following sequence may set
> uncorrected value in MCE registers.
>
> savevm -> loadvm -> (OS clear MCE registers) -> reset -> (MCE registers
> has new (uncorrected) value)
Sorry, I can't follow. Unless I miss some subtle detail, the question is
not when we transfer the mcg_* CPUState fields to the kernel, but when
and how we manipulate them in user space, e.g. on reset. Where are those
fields touched incorrectly between get and put msrs so that we cannot
write them back?
Jan
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- [Qemu-devel] [PATCH v3 05/21] x86: Optionally dump code bytes on cpu_dump_state, (continued)
- [Qemu-devel] [PATCH v3 05/21] x86: Optionally dump code bytes on cpu_dump_state, Jan Kiszka, 2011/01/04
- [Qemu-devel] [PATCH v3 01/21] kvm: Fix coding style violations, Jan Kiszka, 2011/01/04
- [Qemu-devel] [PATCH v3 08/21] kvm: x86: Remove redundant mp_state initialization, Jan Kiszka, 2011/01/04
- [Qemu-devel] [PATCH v3 04/21] kvm: Improve reporting of fatal errors, Jan Kiszka, 2011/01/04
- [Qemu-devel] [PATCH v3 09/21] kvm: x86: Fix xcr0 reset mismerge, Jan Kiszka, 2011/01/04
- [Qemu-devel] [PATCH v3 10/21] kvm: x86: Refactor msr_star/hsave_pa setup and checks, Jan Kiszka, 2011/01/04
- [Qemu-devel] [PATCH v3 11/21] kvm: x86: Reset paravirtual MSRs, Jan Kiszka, 2011/01/04
- [Qemu-devel] [PATCH v3 12/21] kvm: x86: Drop MCE MSRs write back restrictions, Jan Kiszka, 2011/01/04
[Qemu-devel] [PATCH v3 14/21] kvm: x86: Fix !CONFIG_KVM_PARA build, Jan Kiszka, 2011/01/04
[Qemu-devel] [PATCH v3 16/21] kvm: Drop smp_cpus argument from init functions, Jan Kiszka, 2011/01/04
[Qemu-devel] [PATCH v3 19/21] kvm: Flush coalesced mmio buffer on IO window exits, Jan Kiszka, 2011/01/04
[Qemu-devel] [PATCH v3 18/21] kvm: x86: Rework identity map and TSS setup for larger BIOS sizes, Jan Kiszka, 2011/01/04
[Qemu-devel] [PATCH v3 20/21] kvm: Do not use qemu_fair_mutex, Jan Kiszka, 2011/01/04
[Qemu-devel] [PATCH v3 15/21] kvm: x86: Introduce kvmclock device to save/restore its state, Jan Kiszka, 2011/01/04