diff options
| author | Eduardo Habkost <ehabkost@redhat.com> | 2020-06-23 19:01:16 -0400 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2020-06-26 09:39:40 -0400 |
| commit | 730319aef0fcb94f11a4a2d32656437fdde7efdd (patch) | |
| tree | 389d5ba8b684ff387a88bd6f57ac24c94b2e91b5 | |
| parent | c8d7fd059d73a7d3035e379c319034c30ba3dbbf (diff) | |
i386: Mask SVM features if nested SVM is disabled
QEMU incorrectly validates FEAT_SVM feature flags against
GET_SUPPORTED_CPUID even if SVM features are being masked out by
cpu_x86_cpuid(). This can make QEMU print warnings on most AMD
CPU models, even when SVM nesting is disabled (which is the
default).
This bug was never detected before because of a Linux KVM bug:
until Linux v5.6, KVM was not filtering out SVM features in
GET_SUPPORTED_CPUID when nested was disabled. This KVM bug was
fixed in Linux v5.7-rc1, on Linux commit a50718cc3f43 ("KVM:
nSVM: Expose SVM features to L1 iff nested is enabled").
Fix the problem by adding a CPUID_EXT3_SVM dependency to all
FEAT_SVM feature flags in the feature_dependencies table.
Reported-by: Yanan Fu <yfu@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Message-Id: <20200623230116.277409-1-ehabkost@redhat.com>
[Fix testcase. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| -rw-r--r-- | target/i386/cpu.c | 4 | ||||
| -rw-r--r-- | tests/qtest/test-x86-cpuid-compat.c | 4 |
2 files changed, 6 insertions, 2 deletions
diff --git a/target/i386/cpu.c b/target/i386/cpu.c index 06dc013d88..36cbd3d027 100644 --- a/target/i386/cpu.c +++ b/target/i386/cpu.c @@ -1404,6 +1404,10 @@ static FeatureDep feature_dependencies[] = { .from = { FEAT_VMX_SECONDARY_CTLS, VMX_SECONDARY_EXEC_ENABLE_VMFUNC }, .to = { FEAT_VMX_VMFUNC, ~0ull }, }, + { + .from = { FEAT_8000_0001_ECX, CPUID_EXT3_SVM }, + .to = { FEAT_SVM, ~0ull }, + }, }; typedef struct X86RegisterInfo32 { diff --git a/tests/qtest/test-x86-cpuid-compat.c b/tests/qtest/test-x86-cpuid-compat.c index 772287bdb4..7ca1883a29 100644 --- a/tests/qtest/test-x86-cpuid-compat.c +++ b/tests/qtest/test-x86-cpuid-compat.c @@ -256,7 +256,7 @@ int main(int argc, char **argv) "-cpu 486,+invtsc", "xlevel", 0x80000007); /* CPUID[8000_000A].EDX: */ add_cpuid_test("x86/cpuid/auto-xlevel/486/npt", - "-cpu 486,+npt", "xlevel", 0x8000000A); + "-cpu 486,+svm,+npt", "xlevel", 0x8000000A); /* CPUID[C000_0001].EDX: */ add_cpuid_test("x86/cpuid/auto-xlevel2/phenom/xstore", "-cpu phenom,+xstore", "xlevel2", 0xC0000001); @@ -348,7 +348,7 @@ int main(int argc, char **argv) "-machine pc-i440fx-2.4 -cpu SandyBridge,", "xlevel", 0x80000008); add_cpuid_test("x86/cpuid/xlevel-compat/pc-i440fx-2.4/npt-on", - "-machine pc-i440fx-2.4 -cpu SandyBridge,+npt", + "-machine pc-i440fx-2.4 -cpu SandyBridge,+svm,+npt", "xlevel", 0x80000008); /* Test feature parsing */ |