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[Qemu-devel] [PATCH qom-cpu 08/11] target-i386: check/enforce: Check SVM
From: |
Eduardo Habkost |
Subject: |
[Qemu-devel] [PATCH qom-cpu 08/11] target-i386: check/enforce: Check SVM flag support as well |
Date: |
Fri, 4 Jan 2013 20:01:09 -0200 |
When nested SVM is supported, the kernel returns the SVM flag on
GET_SUPPORTED_CPUID[1], so we can check the SVM flag safely on
kvm_check_features_against_host().
I don't know why the original code ignored the SVM flag. Maybe it was
because kvm_cpu_fill_host() used the CPUID instruction directly instead
of GET_SUPPORTED_CPUID
[1] Older kernels (before v2.6.37) returned the SVM flag even if nested
SVM was _not_ supported. So the only cases where this patch should
change behavior is when SVM is being requested by the user or the
CPU model, but not supported by the host. And on these cases we
really want QEMU to abort if the "enforce" option is set.
Signed-off-by: Eduardo Habkost <address@hidden>
---
Cc: Joerg Roedel <address@hidden>
Cc: address@hidden
Cc: address@hidden
Cc: Jiri Denemark <address@hidden>
I'm CCing libvirt people in case having SVM enabled by default may cause
trouble when libvirt starts using the "enforce" flag. I don't know if
libvirt expects most of the QEMU CPU models to have nested SVM enabled.
Changes v2:
- Coding style fix
---
target-i386/cpu.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/target-i386/cpu.c b/target-i386/cpu.c
index ce64b98..a9dd959 100644
--- a/target-i386/cpu.c
+++ b/target-i386/cpu.c
@@ -974,7 +974,7 @@ static int kvm_check_features_against_host(x86_def_t
*guest_def)
{&guest_def->ext2_features, &host_def.ext2_features,
~0, ext2_feature_name, 0x80000001, R_EDX},
{&guest_def->ext3_features, &host_def.ext3_features,
- ~CPUID_EXT3_SVM, ext3_feature_name, 0x80000001, R_ECX}
+ ~0, ext3_feature_name, 0x80000001, R_ECX}
};
assert(kvm_enabled());
--
1.7.11.7
- Re: [Qemu-devel] [PATCH qom-cpu 01/11] target-i386: Don't set any KVM flag by default if KVM is disabled, (continued)
[Qemu-devel] [PATCH qom-cpu 02/11] target-i386: Disable kvm_mmu_op by default on pc-1.4, Eduardo Habkost, 2013/01/04
[Qemu-devel] [PATCH qom-cpu 05/11] target-i386: check/enforce: Fix CPUID leaf numbers on error messages, Eduardo Habkost, 2013/01/04
[Qemu-devel] [PATCH qom-cpu 08/11] target-i386: check/enforce: Check SVM flag support as well,
Eduardo Habkost <=
[Qemu-devel] [PATCH qom-cpu 11/11] target-i386: check/enforce: Check all feature words, Eduardo Habkost, 2013/01/04
Re: [Qemu-devel] [PATCH qom-cpu 00/11] disable-kvm_mmu + -cpu check/enforce fixes (v2), Andreas Färber, 2013/01/07