Messages in this thread | | | Date | Fri, 1 May 2015 11:37:54 +0100 | From | David Vrabel <> | Subject | Re: [Xen-devel] [PATCH] hypervisor/x86/xen: Unset X86_BUG_SYSRET_SS_ATTRS on Xen PV guests |
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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__KERNEL_DS. > > Since the problem that the commit is trying to address would have to be > fixed in the hypervisor (if it in fact exists under Xen) there is no > reason to set X86_BUG_SYSRET_SS_ATTRS flag for PV VPCUs here. > > This can be easily achieved by adding x86_hyper_xen_hvm.set_cpu_features > op which will clear this flag. (And since this structure is no longer > HVM-specific we should do some renaming).
Applied to for-linus-4.1b, thanks.
David
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