Woller, Thomas
2006-Oct-09 21:25 UTC
[Xen-devel] [SVM][PATCH] Add test for SVM Disabled via BIOS
Newer BIOS implementations will be able to disable the SVM feature, although an additional test of an MSR (VMCR 0xC0010114 bit 4) is necessary (set equals disabled). Bit 4 of MSR 0xc0010114 returns 0 (SVM enabled) on machines with older BIOS'' without the SVM disable feature support. Applies cleanly to 11730. Signed-off-by: Wei Huang <wei.huang2@amd.com> Signed-off-by: Tom Woller <thomas.woller@amd.com> Know that it is very late for 3.0.3, would be good to have this code in 3.0.3-rcN if possible. Please apply to xen-unstable.hg Please apply to xen-3.0.3-testing --Tom _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Keir Fraser
2006-Oct-12 13:38 UTC
Re: [Xen-devel] [SVM][PATCH] Add test for SVM Disabled via BIOS
On 9/10/06 22:25, "Woller, Thomas" <thomas.woller@amd.com> wrote:> Newer BIOS implementations will be able to disable the SVM feature, > although an additional test of an MSR (VMCR 0xC0010114 bit 4) is > necessary (set equals disabled). Bit 4 of MSR 0xc0010114 returns 0 (SVM > enabled) on machines with older BIOS'' without the SVM disable feature > support.What happens if it is disabled and we ignore the MSR? Does everything just work, or does, for example, the write to EFER.SVME fault? -- Keir _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Woller, Thomas
2006-Oct-12 15:01 UTC
RE: [Xen-devel] [SVM][PATCH] Add test for SVM Disabled via BIOS
> What happens if it is disabled and we ignore the MSR? Does > everything just work, or does, for example, the write to > EFER.SVME fault?We experienced a #GP during hv boot setting EFER.SVME. So, the hv never came up. Should also get a #UD if try to execute one of the AMD-V instructions first.> Does this new MSR have a name?VM_CR (Virtual Machine Control Register in BKDG to be out in public spec soon) --Tom _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Keir Fraser
2006-Oct-12 15:37 UTC
Re: [Xen-devel] [SVM][PATCH] Add test for SVM Disabled via BIOS
On 12/10/06 16:01, "Woller, Thomas" <thomas.woller@amd.com> wrote:>> What happens if it is disabled and we ignore the MSR? Does >> everything just work, or does, for example, the write to >> EFER.SVME fault? > We experienced a #GP during hv boot setting EFER.SVME. So, the hv never > came up. Should also get a #UD if try to execute one of the AMD-V > instructions first. > >> Does this new MSR have a name? > VM_CR (Virtual Machine Control Register in BKDG to be out in public spec > soon)I''ve taken the patch as-is for now. We can add names later. Turns out the patch will make 3.0.3, as I''ll be spinning an -rc4 tomorrow which fixes the IA64 issues, among others. -- Keir _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel