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Re: [PATCH v2] x86/mce: fix wrong no-return-ip logic in do_machine_check
From: |
Aili Yao |
Subject: |
Re: [PATCH v2] x86/mce: fix wrong no-return-ip logic in do_machine_check() |
Date: |
Wed, 24 Mar 2021 10:59:50 +0800 |
On Wed, 24 Feb 2021 10:39:21 +0800
Aili Yao <yaoaili@kingsoft.com> wrote:
> On Tue, 23 Feb 2021 16:12:43 +0000
> "Luck, Tony" <tony.luck@intel.com> wrote:
>
> > > What I think is qemu has not an easy to get the MCE signature from host
> > > or currently no methods for this
> > > So qemu treat all AR will be No RIPV, Do more is better than do less.
> >
> > RIPV would be important in the guest in the case where the guest can fix
> > the problem that caused
> > the machine check and return to the failed instruction to continue.
> >
> > I think the only case where this happens is a fault in a read-only page
> > mapped from a file (typically
> > code page, but could be a data page). In this case memory-failure() unmaps
> > the page with the posion
> > but Linux can recover by reading data from the file into a new page.
> >
> > Other cases we send SIGBUS (so go to the signal handler instead of to the
> > faulting instruction).
> >
> > So it would be good if the state of RIPV could be added to the signal state
> > sent to qemu. If that
> > isn't possible, then this full recovery case turns into another SIGBUS
> > case.
>
> This KVM and VM case of failing recovery for SRAR is just one scenario I
> think,
> If Intel guarantee that when memory SRAR is triggered, RIPV will always be
> set, then it's the job of qemu to
> set the RIPV instead.
> Or if When SRAR is triggered with RIPV cleared, the same issue will be true
> for host.
>
> And I think it's better for VM to know the real RIPV value, It need more work
> in qemu and kernel if possible.
>
> Thanks
> Aili Yao
ADD this topic to qemu list, this is really one bad issue.
Issue report:
when VM receive one SRAR memory failure from host, it all has RIPV cleared, and
then vm process it and trigger one panic!
Can any qemu maintainer fix this?
Suggestion:
qemu get the true value of RIPV from host, the inject it to VM accordingly.
Thanks
Aili Yao!
- Re: [PATCH v2] x86/mce: fix wrong no-return-ip logic in do_machine_check(),
Aili Yao <=