Re: [Xen-devel] [PATCH for-4.5] x86/HVM: Partial revert of 28b4baacd5

2014-11-25 Thread Jan Beulich
>>> On 25.11.14 at 13:10, wrote: > On 25/11/14 11:31, Jan Beulich wrote: > On 25.11.14 at 11:58, wrote: >>> On 25/11/14 10:46, Andrew Cooper wrote: On 25/11/14 10:42, Jan Beulich wrote: On 25.11.14 at 11:08, wrote: >> A failed vmentry is overwhelmingly likely to be caused b

Re: [Xen-devel] [PATCH for-4.5] x86/HVM: Partial revert of 28b4baacd5

2014-11-25 Thread Andrew Cooper
On 25/11/14 11:31, Jan Beulich wrote: On 25.11.14 at 11:58, wrote: >> On 25/11/14 10:46, Andrew Cooper wrote: >>> On 25/11/14 10:42, Jan Beulich wrote: >>> On 25.11.14 at 11:08, wrote: > A failed vmentry is overwhelmingly likely to be caused by corrupt VMCS >> state. > As a resu

Re: [Xen-devel] [PATCH for-4.5] x86/HVM: Partial revert of 28b4baacd5

2014-11-25 Thread Jan Beulich
>>> On 25.11.14 at 11:58, wrote: > On 25/11/14 10:46, Andrew Cooper wrote: >> On 25/11/14 10:42, Jan Beulich wrote: >> On 25.11.14 at 11:08, wrote: A failed vmentry is overwhelmingly likely to be caused by corrupt VMCS > state. As a result, injecting a fault and retrying the the vm

Re: [Xen-devel] [PATCH for-4.5] x86/HVM: Partial revert of 28b4baacd5

2014-11-25 Thread Andrew Cooper
On 25/11/14 10:46, Andrew Cooper wrote: > On 25/11/14 10:42, Jan Beulich wrote: > On 25.11.14 at 11:08, wrote: >>> A failed vmentry is overwhelmingly likely to be caused by corrupt VMCS >>> state. >>> As a result, injecting a fault and retrying the the vmentry is likely to >>> fail >>> in th

Re: [Xen-devel] [PATCH for-4.5] x86/HVM: Partial revert of 28b4baacd5

2014-11-25 Thread Jan Beulich
>>> On 25.11.14 at 11:46, wrote: > On 25/11/14 10:42, Jan Beulich wrote: > On 25.11.14 at 11:08, wrote: >>> A failed vmentry is overwhelmingly likely to be caused by corrupt VMCS > state. >>> As a result, injecting a fault and retrying the the vmentry is likely to >>> fail >>> in the same w

Re: [Xen-devel] [PATCH for-4.5] x86/HVM: Partial revert of 28b4baacd5

2014-11-25 Thread Andrew Cooper
On 25/11/14 10:42, Jan Beulich wrote: On 25.11.14 at 11:08, wrote: >> A failed vmentry is overwhelmingly likely to be caused by corrupt VMCS state. >> As a result, injecting a fault and retrying the the vmentry is likely to >> fail >> in the same way. > That's not all that unlikely - remembe

Re: [Xen-devel] [PATCH for-4.5] x86/HVM: Partial revert of 28b4baacd5

2014-11-25 Thread Tim Deegan
At 10:08 + on 25 Nov (1416906538), Andrew Cooper wrote: > A failed vmentry is overwhelmingly likely to be caused by corrupt VMCS state. > As a result, injecting a fault and retrying the the vmentry is likely to fail > in the same way. In particular, the guest's privilege level won't change unt

Re: [Xen-devel] [PATCH for-4.5] x86/HVM: Partial revert of 28b4baacd5

2014-11-25 Thread Jan Beulich
>>> On 25.11.14 at 11:08, wrote: > A failed vmentry is overwhelmingly likely to be caused by corrupt VMCS state. > As a result, injecting a fault and retrying the the vmentry is likely to > fail > in the same way. That's not all that unlikely - remember that the change was prompted by the XSA-11

[Xen-devel] [PATCH for-4.5] x86/HVM: Partial revert of 28b4baacd5

2014-11-25 Thread Andrew Cooper
A failed vmentry is overwhelmingly likely to be caused by corrupt VMCS state. As a result, injecting a fault and retrying the the vmentry is likely to fail in the same way. While crashing a guest because userspace tickled a hypervisor bug to get up invalid VMCS state is bad (and usually warrants a