Re: [Xen-devel] [PATCH] hypervisor/x86/xen: Unset X86_BUG_SYSRET_SS_ATTRS on Xen PV guests

2015-05-02 Thread Sander Eikelenboom
Friday, May 1, 2015, 12:37:54 PM, you wrote: > On 30/04/15 20:08, Boris Ostrovsky wrote: >> Commit 61f01dd941ba ("x86_64, asm: Work around AMD SYSRET SS descriptor >> attribute issue") makes AMD processors set SS to __KERNEL_DS in >> __switch_to() to deal with cases when SS is NULL. >> >> This b

Re: [Xen-devel] [PATCH] hypervisor/x86/xen: Unset X86_BUG_SYSRET_SS_ATTRS on Xen PV guests

2015-05-01 Thread David Vrabel
On 30/04/15 20:08, Boris Ostrovsky wrote: > Commit 61f01dd941ba ("x86_64, asm: Work around AMD SYSRET SS descriptor > attribute issue") makes AMD processors set SS to __KERNEL_DS in > __switch_to() to deal with cases when SS is NULL. > > This breaks Xen PV guests who do not want to load SS with__K

Re: [PATCH] hypervisor/x86/xen: Unset X86_BUG_SYSRET_SS_ATTRS on Xen PV guests

2015-04-30 Thread Boris Ostrovsky
On 04/30/2015 03:35 PM, Andy Lutomirski wrote: On Thu, Apr 30, 2015 at 12:30 PM, Boris Ostrovsky wrote: On 04/30/2015 03:17 PM, Andy Lutomirski wrote: On Thu, Apr 30, 2015 at 12:08 PM, Boris Ostrovsky wrote: Commit 61f01dd941ba ("x86_64, asm: Work around AMD SYSRET SS descriptor attribute is

Re: [PATCH] hypervisor/x86/xen: Unset X86_BUG_SYSRET_SS_ATTRS on Xen PV guests

2015-04-30 Thread Andy Lutomirski
On Thu, Apr 30, 2015 at 12:30 PM, Boris Ostrovsky wrote: > On 04/30/2015 03:17 PM, Andy Lutomirski wrote: >> >> On Thu, Apr 30, 2015 at 12:08 PM, Boris Ostrovsky >> wrote: >>> >>> Commit 61f01dd941ba ("x86_64, asm: Work around AMD SYSRET SS descriptor >>> attribute issue") makes AMD processors se

Re: [PATCH] hypervisor/x86/xen: Unset X86_BUG_SYSRET_SS_ATTRS on Xen PV guests

2015-04-30 Thread Boris Ostrovsky
On 04/30/2015 03:17 PM, Andy Lutomirski wrote: On Thu, Apr 30, 2015 at 12:08 PM, Boris Ostrovsky wrote: Commit 61f01dd941ba ("x86_64, asm: Work around AMD SYSRET SS descriptor attribute issue") makes AMD processors set SS to __KERNEL_DS in __switch_to() to deal with cases when SS is NULL. This

Re: [PATCH] hypervisor/x86/xen: Unset X86_BUG_SYSRET_SS_ATTRS on Xen PV guests

2015-04-30 Thread Andy Lutomirski
On Thu, Apr 30, 2015 at 12:08 PM, Boris Ostrovsky wrote: > Commit 61f01dd941ba ("x86_64, asm: Work around AMD SYSRET SS descriptor > attribute issue") makes AMD processors set SS to __KERNEL_DS in > __switch_to() to deal with cases when SS is NULL. > > This breaks Xen PV guests who do not want to

[PATCH] hypervisor/x86/xen: Unset X86_BUG_SYSRET_SS_ATTRS on Xen PV guests

2015-04-30 Thread Boris Ostrovsky
Commit 61f01dd941ba ("x86_64, asm: Work around AMD SYSRET SS descriptor attribute issue") makes AMD processors set SS to __KERNEL_DS in __switch_to() to deal with cases when SS is NULL. This breaks Xen PV guests who do not want to load SS with__KERNEL_DS. Since the problem that the commit is tryi