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Re: [Qemu-devel] [Xen-devel] [PATCH][XSA-126] xen: limit guest control o
From: |
Michael S. Tsirkin |
Subject: |
Re: [Qemu-devel] [Xen-devel] [PATCH][XSA-126] xen: limit guest control of PCI command register |
Date: |
Mon, 20 Apr 2015 16:32:12 +0200 |
On Mon, Apr 20, 2015 at 03:08:09PM +0100, Jan Beulich wrote:
> >>> On 20.04.15 at 15:43, <address@hidden> wrote:
> > On Mon, Apr 13, 2015 at 01:51:06PM +0100, Jan Beulich wrote:
> >> >>> On 13.04.15 at 14:47, <address@hidden> wrote:
> >> > Can you check device capabilities register, offset 0x4 within
> >> > pci express capability structure?
> >> > Bit 15 is 15 Role-Based Error Reporting.
> >> > Is it set?
> >> >
> >> > The spec says:
> >> >
> >> > 15
> >> > On platforms where robust error handling and PC-compatible
> >> > Configuration
> >> > Space probing is
> >> > required, it is suggested that software or firmware have the
> >> > Unsupported
> >> > Request Reporting Enable
> >> > bit Set for Role-Based Error Reporting Functions, but clear for 1.0a
> >> > Functions. Software or
> >> > firmware can distinguish the two classes of Functions by examining the
> >> > Role-Based Error Reporting
> >> > bit in the Device Capabilities register.
> >>
> >> Yes, that bit is set.
> >
> > curiouser and curiouser.
> >
> > So with functions that do support Role-Based Error Reporting, we have
> > this:
> >
> >
> > With device Functions implementing Role-Based Error Reporting, setting
> > the
> > Unsupported Request
> > Reporting Enable bit will not interfere with PC-compatible
> > Configuration
> > Space probing, assuming
> > that the severity for UR is left at its default of non-fatal. However,
> > setting the Unsupported Request
> > Reporting Enable bit will enable the Function to report UR errors 97
> > detected with posted Requests,
> > helping avoid this case for potential silent data corruption.
>
> I still don't see what the PC-compatible config space probing has to
> do with our issue.
I'm not sure but I think it's listed here because it causes a ton of URs
when device scan probes unimplemented functions.
> > did firmware reconfigure this device to report URs as fatal errors then?
>
> No, the Unsupported Request Error Serverity flag is zero.
>
> Jan
OK, that's the correct configuration, so how come the box crashes when
there's a UR then?
--
MST
- Re: [Qemu-devel] [Xen-devel] [PATCH][XSA-126] xen: limit guest control of PCI command register, (continued)
- Re: [Qemu-devel] [Xen-devel] [PATCH][XSA-126] xen: limit guest control of PCI command register, Michael S. Tsirkin, 2015/04/01
- Re: [Qemu-devel] [Xen-devel] [PATCH][XSA-126] xen: limit guest control of PCI command register, Jan Beulich, 2015/04/13
- Re: [Qemu-devel] [Xen-devel] [PATCH][XSA-126] xen: limit guest control of PCI command register, Michael S. Tsirkin, 2015/04/13
- Re: [Qemu-devel] [Xen-devel] [PATCH][XSA-126] xen: limit guest control of PCI command register, Jan Beulich, 2015/04/13
- Re: [Qemu-devel] [Xen-devel] [PATCH][XSA-126] xen: limit guest control of PCI command register, Michael S. Tsirkin, 2015/04/13
- Re: [Qemu-devel] [Xen-devel] [PATCH][XSA-126] xen: limit guest control of PCI command register, Jan Beulich, 2015/04/13
- Re: [Qemu-devel] [Xen-devel] [PATCH][XSA-126] xen: limit guest control of PCI command register, Michael S. Tsirkin, 2015/04/13
- Re: [Qemu-devel] [Xen-devel] [PATCH][XSA-126] xen: limit guest control of PCI command register, Jan Beulich, 2015/04/13
- Re: [Qemu-devel] [Xen-devel] [PATCH][XSA-126] xen: limit guest control of PCI command register, Michael S. Tsirkin, 2015/04/20
- Re: [Qemu-devel] [Xen-devel] [PATCH][XSA-126] xen: limit guest control of PCI command register, Jan Beulich, 2015/04/20
- Re: [Qemu-devel] [Xen-devel] [PATCH][XSA-126] xen: limit guest control of PCI command register,
Michael S. Tsirkin <=
- Re: [Qemu-devel] [Xen-devel] [PATCH][XSA-126] xen: limit guest control of PCI command register, Jan Beulich, 2015/04/20
Re: [Qemu-devel] [Xen-devel] [PATCH][XSA-126] xen: limit guest control of PCI command register, Ian Campbell, 2015/04/01