From: Xiaoyao Li <xiaoyao.li@intel.com>
To: Paolo Bonzini <pbonzini@redhat.com>,
Marcelo Tosatti <mtosatti@redhat.com>
Cc: qemu-devel@nongnu.org, xiaoyao.li@intel.com
Subject: [PATCH] targer/i386/cpu: Fix CPUID_HT exposure
Date: Tue, 10 Oct 2023 02:05:39 -0400 [thread overview]
Message-ID: <20231010060539.210258-1-xiaoyao.li@intel.com> (raw)
When explicitly booting a multiple vcpus vm with "-cpu +ht", it gets
warning of
warning: host doesn't support requested feature: CPUID.01H:EDX.ht [bit 28]
Make CPUID_HT as supported unconditionally can resolve the warning.
However it introduces another issue that it also expose CPUID_HT to
guest when "-cpu host/max" with only 1 vcpu. To fix this, need mark
CPUID_HT as the no_autoenable_flags.
Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
---
target/i386/cpu.c | 1 +
target/i386/kvm/kvm.c | 2 ++
2 files changed, 3 insertions(+)
diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index cec5d2b7b65e..32c077455f04 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -778,6 +778,7 @@ FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
},
.cpuid = {.eax = 1, .reg = R_EDX, },
.tcg_features = TCG_FEATURES,
+ .no_autoenable_flags = CPUID_HT,
},
[FEAT_1_ECX] = {
.type = CPUID_FEATURE_WORD,
diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c
index f6c7f7e26869..ab72bcdfad13 100644
--- a/target/i386/kvm/kvm.c
+++ b/target/i386/kvm/kvm.c
@@ -373,6 +373,8 @@ uint32_t kvm_arch_get_supported_cpuid(KVMState *s, uint32_t function,
if (function == 1 && reg == R_EDX) {
/* KVM before 2.6.30 misreports the following features */
ret |= CPUID_MTRR | CPUID_PAT | CPUID_MCE | CPUID_MCA;
+ /* KVM never reports CPUID_HT but QEMU can support when vcpus > 1 */
+ ret |= CPUID_HT;
} else if (function == 1 && reg == R_ECX) {
/* We can set the hypervisor flag, even if KVM does not return it on
* GET_SUPPORTED_CPUID
base-commit: cea3ea670fe265421131aad90c36fbb87bc4d206
--
2.34.1
next reply other threads:[~2023-10-10 6:06 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-10 6:05 Xiaoyao Li [this message]
2023-10-10 14:20 ` [PATCH] targer/i386/cpu: Fix CPUID_HT exposure Paolo Bonzini
2023-10-12 9:39 ` Farrah Chen
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