Re: [Xen-devel] [PATCH] x86/HVM: Merge HVM and PVH hypercall tables

[Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>]

On 12/14/2015 02:51 AM, Jan Beulich wrote:
> > > > On 11.12.15 at 17:50, <boris.ostrovsky@xxxxxxxxxx> wrote:
> > On 12/10/2015 11:53 AM, Boris Ostrovsky wrote:
> > > Especially given that PVH dom0 is not booting for me, as I just found
> > > out:
> > >
> > > ...
> > > (XEN) d0v0 EPT violation 0x1aa (-w-/r-x) gpa 0x000000c0008116 mfn
> > > 0xc0008 type 5
> > > (XEN) d0v0 Walking EPT tables for GFN c0008:
> > > (XEN) d0v0  epte 800000082bf50007
> > > (XEN) d0v0  epte 800000082bf19007
> > > (XEN) d0v0  epte 800000043c6f9007
> > > (XEN) d0v0  epte 80500000c0008805
> > > (XEN) d0v0  --- GLA 0xffffc90020008116
> > > (XEN) domain_crash called from vmx.c:2816
> > > (XEN) Domain 0 (vcpu#0) crashed on cpu#0:
> > > (XEN) ----[ Xen-4.7-unstable  x86_64  debug=y  Tainted:    C ]----
> > > (XEN) CPU:    0
> > > (XEN) RIP:    0010:[<ffffffff816150dc>]
> > > (XEN) RFLAGS: 0000000000010046   CONTEXT: hvm guest (d0v0)
> > > (XEN) rax: 000000000000001d   rbx: 0000000000000000   rcx:
> > > ffff88014700f9b8
> > > (XEN) rdx: 00000000000000ff   rsi: 0000000000000000   rdi:
> > > 0000000000000000
> > > (XEN) rbp: ffff88014700fa18   rsp: ffff88014700f9e8   r8:
> > > ffff88014700f9c0
> > > (XEN) r9:  000000000000001d   r10: ffffffff8189c7f0   r11:
> > > 0000000000000000
> > > (XEN) r12: ffffc90020008000   r13: ffffc90020008116   r14:
> > > 0000000000000002
> > > (XEN) r15: 000000000000001d   cr0: 0000000080050033   cr4:
> > > 00000000000406f0
> > > (XEN) cr3: 0000000001c0e000   cr2: 0000000000000000
> > > (XEN) ds: 0000   es: 0000   fs: 0000   gs: 0000   ss: 0000   cs: 0010
> > > (XEN) Guest stack trace from rsp=ffff88014700f9e8:
> > > (XEN)   Fault while accessing guest memory.
> > > (XEN) Hardware Dom0 crashed: rebooting machine in 5 seconds.
> > >
> > >
> > > We haven't been running regression tests for PVH dom0 so I don't know
> > > how long this has been broken.
> > This is broken by 9256f66c1606 ("x86/PCI: intercept all PV Dom0 MMCFG
> > writes").
> Well, I can't find any hookup of the write emulation logic for PVH
> at all in ept_handle_violation() or hvm_hap_nested_page_fault(),
> i.e. it looks to me as if this was broken already before, just that
> for the limited set of devices that had their MMCFG space marked
> r/o this went unnoticed (iow perhaps a missing FIXME annotation).
> I'll see to find time to look into this, but I can't really predict when
> I might get around to it.
I added handling for MMCFG to ept_handle_violation() and that indeed 
fixed it (but it should really go to hvm_hap_nested_page_fault() since 
we will want AMD support for that as well).
I'll try to come up with a patch in the next day or two.

-boris

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