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Re: [Xen-devel] [Patch 0/6] Xen vMCE implement

>>> On 27.07.12 at 17:28, "Liu, Jinsong" <jinsong.liu@xxxxxxxxx> wrote:
> Comments?

It didn't get lost, but I didn't get to it yet. Some time next week,


> Liu, Jinsong wrote:
>> Hi,
>> These patches are Xen vMCE implement, among them
>> ===================
>> Patch 1: This patch is a middle-work patch, prepare for future new
>> vMCE model. It remove mci_ctl array, and keep MCi_CTL all 1's. 
>> Patch 2: This patch is a middle-work patch, prepare for future new
>> vMCE model. It remove mcg_ctl, disable MCG_CTL_P, and set bank number
>> to 2.  
>> Patch 3: vMCE emulation
>> This patch provides virtual MCE support to guest. It emulates a
>> simple and clean MCE MSRs interface to guest by faking caps to guest
>> if needed and masking caps if unnecessary:  
>> 1. Providing a well-defined MCG_CAP to guest, filter out un-necessary
>> caps and provide only guest needed caps; 
>> 2. Disabling MCG_CTL to avoid model specific;
>> 3. Sticking all 1's to MCi_CTL to guest to avoid model specific;
>> 4. Enabling CMCI cap but never really inject to guest to prevent
>> polling periodically; 
>> 5. Masking MSCOD field of MCi_STATUS to avoid model specific;
>> 6. Keeping natural semantics by per-vcpu instead of per-domain
>> variables; 
>> 7. Using bank1 and reserving bank0 to work around 'bank0 quirk' of
>> some very old processors; 
>> 8. Cleaning some vMCE# injection logic which shared by Intel and AMD
>> but useless under new vMCE implement; 
>> 9. Keeping compatilbe w/ old xen version which has been backported to
>> SLES11 SP2, so that old vMCE would not blocked when migrate to new
>> vMCE;  
>> Patch 4: vMCE injection
>> In our test for win8 guest mce, we find a bug that no matter what
>> SRAO/SRAR error xen inject to win8 guest, it always reboot. The root
>> cause is, current Xen vMCE logic inject vMCE# only to vcpu0, this is
>> not correct for Intel MCE (Under Intel arch, h/w generate MCE# to all
>> CPUs). This patch fix vMCE injection bug, injecting vMCE# to all
>> vcpus.    
>> Patch 5: vMCE save and restore
>> This patch provide vMCE save/restore when migration.
>> 1. MCG_CAP is well-defined. However, considering future cap
>> extension, we keep save/restore logic that Jan implement at c/s
>> 24887;  
>> 2. MCi_CTL2 initialized by guestos when booting, so need save/restore
>> otherwise guest would surprise; 
>> 3. Other MSRs do not need save/restore since they are either
>> error-related and pointless to save/restore, or, unified among all
>> vMCE platform;  
>> Patch 6: Cleanup guest vMCE check
>> This patch simplify vMCE logic by removing guest vMCE check, since
>> hypervisor should be agnostic to guest. 
>> With guest vMCE check, hypervisor would actively kill guest when
>> guest vMCE not ready. Without guest vMCE check, hypervisor would
>> always inject vMCE to guest: if guest ready it would happily handle
>> it, and if guest not ready, it automatically kill itself.
>> ====================   
>> These patches have been tested w/ Linux and Windows 8 guestos, and
>> worked fine. 
>> Considering Intel and AMD common vMCE interface to guest, these
>> patches are mainly put in vmce.c (except mci_ctl2 in intel specific
>> code since this MSRs are supported by Intel only). AMD code could
>> update them according to AMD's specific requirement.   
>> These patches didn't handle the corner case 'MCE occur when live
>> migration'. We have draftly done the patch for the corner case but
>> meet issue now (seems caused from Xen live migration logic itself, we
>> are debugging it now, and would present soon when it fixed).   
>> Thanks,
>> Jinsong
>> _______________________________________________
>> Xen-devel mailing list
>> Xen-devel@xxxxxxxxxxxxx 
>> http://lists.xen.org/xen-devel 

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