diff options
| author | Vitaly Kuznetsov <vkuznets@redhat.com> | 2024-09-17 18:00:49 +0200 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2024-10-17 12:30:21 +0200 |
| commit | 7d7b9c7655a26e09c800ef40373078a80e90d9f3 (patch) | |
| tree | d0892d79e8633f89372df05410a51105f904a233 /target/i386 | |
| parent | bbf3810f2c4f97bd7a1982d3e0ff0f00295b8169 (diff) | |
target/i386: Exclude 'hv-syndbg' from 'hv-passthrough'
Windows with Hyper-V role enabled doesn't boot with 'hv-passthrough' when
no debugger is configured, this significantly limits the usefulness of the
feature as there's no support for subtracting Hyper-V features from CPU
flags at this moment (e.g. "-cpu host,hv-passthrough,-hv-syndbg" does not
work). While this is also theoretically fixable, 'hv-syndbg' is likely
very special and unneeded in the default set. Genuine Hyper-V doesn't seem
to enable it either.
Introduce 'skip_passthrough' flag to 'kvm_hyperv_properties' and use it as
one-off to skip 'hv-syndbg' when enabling features in 'hv-passthrough'
mode. Note, "-cpu host,hv-passthrough,hv-syndbg" can still be used if
needed.
As both 'hv-passthrough' and 'hv-syndbg' are debug features, the change
should not have any effect on production environments.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Link: https://lore.kernel.org/r/20240917160051.2637594-3-vkuznets@redhat.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'target/i386')
| -rw-r--r-- | target/i386/kvm/kvm.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c index 1ec4977a8e..fd9f198892 100644 --- a/target/i386/kvm/kvm.c +++ b/target/i386/kvm/kvm.c @@ -934,6 +934,7 @@ static struct { uint32_t bits; } flags[2]; uint64_t dependencies; + bool skip_passthrough; } kvm_hyperv_properties[] = { [HYPERV_FEAT_RELAXED] = { .desc = "relaxed timing (hv-relaxed)", @@ -1062,7 +1063,8 @@ static struct { {.func = HV_CPUID_FEATURES, .reg = R_EDX, .bits = HV_FEATURE_DEBUG_MSRS_AVAILABLE} }, - .dependencies = BIT(HYPERV_FEAT_SYNIC) | BIT(HYPERV_FEAT_RELAXED) + .dependencies = BIT(HYPERV_FEAT_SYNIC) | BIT(HYPERV_FEAT_RELAXED), + .skip_passthrough = true, }, [HYPERV_FEAT_MSR_BITMAP] = { .desc = "enlightened MSR-Bitmap (hv-emsr-bitmap)", @@ -1471,7 +1473,8 @@ bool kvm_hyperv_expand_features(X86CPU *cpu, Error **errp) * hv_build_cpuid_leaf() uses this info to build guest CPUIDs. */ for (feat = 0; feat < ARRAY_SIZE(kvm_hyperv_properties); feat++) { - if (hyperv_feature_supported(cs, feat)) { + if (hyperv_feature_supported(cs, feat) && + !kvm_hyperv_properties[feat].skip_passthrough) { cpu->hyperv_features |= BIT(feat); } } |