| Message ID | 20190516125807.17025-1-bwiedemann@suse.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | i386: Fix nested SVM on older Opterons | expand |
* Bernhard M. Wiedemann (bwiedemann@suse.de) wrote: > Without this patch, a VM on a Opteron G3 host will have the svm flag, but > the kvm-amd module fails to load in there, complaining that it needs > cpuid 0x8000000a > > I have successfully built and tested this for 3+ years in production > on Opteron G3 servers. > > Signed-off-by: Bernhard M. Wiedemann <bwiedemann@suse.de> > --- > target/i386/cpu.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/target/i386/cpu.c b/target/i386/cpu.c > index 722c5514d4..df1d81ded8 100644 > --- a/target/i386/cpu.c > +++ b/target/i386/cpu.c > @@ -2723,7 +2723,7 @@ static X86CPUDefinition builtin_x86_defs[] = { > CPUID_EXT_SSE3, > .features[FEAT_8000_0001_EDX] = > CPUID_EXT2_LM | CPUID_EXT2_NX | CPUID_EXT2_SYSCALL, > - .xlevel = 0x80000008, > + .xlevel = 0x8000000A, > .model_id = "AMD Opteron 240 (Gen 1 Class Opteron)", > }, > { > @@ -2745,7 +2745,7 @@ static X86CPUDefinition builtin_x86_defs[] = { > CPUID_EXT2_LM | CPUID_EXT2_NX | CPUID_EXT2_SYSCALL, > .features[FEAT_8000_0001_ECX] = > CPUID_EXT3_SVM | CPUID_EXT3_LAHF_LM, > - .xlevel = 0x80000008, > + .xlevel = 0x8000000A, > .model_id = "AMD Opteron 22xx (Gen 2 Class Opteron)", > }, > { > @@ -2770,7 +2770,7 @@ static X86CPUDefinition builtin_x86_defs[] = { > .features[FEAT_8000_0001_ECX] = > CPUID_EXT3_MISALIGNSSE | CPUID_EXT3_SSE4A | > CPUID_EXT3_ABM | CPUID_EXT3_SVM | CPUID_EXT3_LAHF_LM, > - .xlevel = 0x80000008, > + .xlevel = 0x8000000A, > .model_id = "AMD Opteron 23xx (Gen 3 Class Opteron)", > }, > { cc'ing in Bandan and Eduardo, I suspect these need to have compatibility entries on the machine types so that old machine types don't notice the improvement. Dave > -- > 2.16.4 > > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
On Thu, May 23, 2019 at 07:57:38PM +0100, Dr. David Alan Gilbert wrote: > * Bernhard M. Wiedemann (bwiedemann@suse.de) wrote: > > Without this patch, a VM on a Opteron G3 host will have the svm flag, but > > the kvm-amd module fails to load in there, complaining that it needs > > cpuid 0x8000000a > > > > I have successfully built and tested this for 3+ years in production > > on Opteron G3 servers. Have you reproduced the bug on QEMU 2.8 or newer? The problem you describe should be fixed by the following commit (from ~2.5 years ago). commit 0c3d7c0051576d220e6da0a8ac08f2d8482e2f0b Author: Eduardo Habkost <ehabkost@redhat.com> Date: Wed Sep 21 15:01:35 2016 -0300 target-i386: Enable CPUID[0x8000000A] if SVM is enabled SVM needs CPUID[0x8000000A] to be available. So if SVM is enabled in a CPU model or explicitly in the command-line, adjust CPUID xlevel to expose the CPUID[0x8000000A] leaf. Reviewed-by: Richard Henderson <rth@twiddle.net> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
On 23/05/2019 23.27, Eduardo Habkost wrote: > On Thu, May 23, 2019 at 07:57:38PM +0100, Dr. David Alan Gilbert wrote: >> * Bernhard M. Wiedemann (bwiedemann@suse.de) wrote: >>> Without this patch, a VM on a Opteron G3 host will have the svm flag, but >>> the kvm-amd module fails to load in there, complaining that it needs >>> cpuid 0x8000000a >>> >>> I have successfully built and tested this for 3+ years in production >>> on Opteron G3 servers. > > Have you reproduced the bug on QEMU 2.8 or newer? The problem > you describe should be fixed by the following commit (from ~2.5 > years ago). > > commit 0c3d7c0051576d220e6da0a8ac08f2d8482e2f0b > target-i386: Enable CPUID[0x8000000A] if SVM is enabled I was still on qemu-2.6.2 so it is good to know that this might work out of the box with 2.8+ Thanks for the pointer.
diff --git a/target/i386/cpu.c b/target/i386/cpu.c index 722c5514d4..df1d81ded8 100644 --- a/target/i386/cpu.c +++ b/target/i386/cpu.c @@ -2723,7 +2723,7 @@ static X86CPUDefinition builtin_x86_defs[] = { CPUID_EXT_SSE3, .features[FEAT_8000_0001_EDX] = CPUID_EXT2_LM | CPUID_EXT2_NX | CPUID_EXT2_SYSCALL, - .xlevel = 0x80000008, + .xlevel = 0x8000000A, .model_id = "AMD Opteron 240 (Gen 1 Class Opteron)", }, { @@ -2745,7 +2745,7 @@ static X86CPUDefinition builtin_x86_defs[] = { CPUID_EXT2_LM | CPUID_EXT2_NX | CPUID_EXT2_SYSCALL, .features[FEAT_8000_0001_ECX] = CPUID_EXT3_SVM | CPUID_EXT3_LAHF_LM, - .xlevel = 0x80000008, + .xlevel = 0x8000000A, .model_id = "AMD Opteron 22xx (Gen 2 Class Opteron)", }, { @@ -2770,7 +2770,7 @@ static X86CPUDefinition builtin_x86_defs[] = { .features[FEAT_8000_0001_ECX] = CPUID_EXT3_MISALIGNSSE | CPUID_EXT3_SSE4A | CPUID_EXT3_ABM | CPUID_EXT3_SVM | CPUID_EXT3_LAHF_LM, - .xlevel = 0x80000008, + .xlevel = 0x8000000A, .model_id = "AMD Opteron 23xx (Gen 3 Class Opteron)", }, {
Without this patch, a VM on a Opteron G3 host will have the svm flag, but the kvm-amd module fails to load in there, complaining that it needs cpuid 0x8000000a I have successfully built and tested this for 3+ years in production on Opteron G3 servers. Signed-off-by: Bernhard M. Wiedemann <bwiedemann@suse.de> --- target/i386/cpu.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)