From: Maxim Levitsky <mlevitsk@redhat.com>
To: kvm@vger.kernel.org
Cc: Jim Mattson <jmattson@google.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Borislav Petkov <bp@alien8.de>, Joerg Roedel <joro@8bytes.org>,
Ingo Molnar <mingo@redhat.com>,
Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
linux-kernel@vger.kernel.org,
Sean Christopherson <seanjc@google.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
Maxim Levitsky <mlevitsk@redhat.com>
Subject: [PATCH 7/8] KVM: x86: SVM: fix tsc scaling when the host doesn't support it
Date: Tue, 22 Mar 2022 19:24:48 +0200 [thread overview]
Message-ID: <20220322172449.235575-8-mlevitsk@redhat.com> (raw)
In-Reply-To: <20220322172449.235575-1-mlevitsk@redhat.com>
It was decided that when TSC scaling is not supported,
the virtual MSR_AMD64_TSC_RATIO should still have the default '1.0'
value.
However in this case kvm_max_tsc_scaling_ratio is not set,
which breaks various assumptions.
Fix this by always calculating kvm_max_tsc_scaling_ratio
regardless of host support.
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
---
arch/x86/kvm/svm/svm.c | 4 ++--
arch/x86/kvm/vmx/vmx.c | 7 +++----
arch/x86/kvm/x86.c | 4 +---
3 files changed, 6 insertions(+), 9 deletions(-)
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index fb31ed01086c..acf04cf4ed2a 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -4763,10 +4763,10 @@ static __init int svm_hardware_setup(void)
} else {
pr_info("TSC scaling supported\n");
kvm_has_tsc_control = true;
- kvm_max_tsc_scaling_ratio = SVM_TSC_RATIO_MAX;
- kvm_tsc_scaling_ratio_frac_bits = 32;
}
}
+ kvm_max_tsc_scaling_ratio = SVM_TSC_RATIO_MAX;
+ kvm_tsc_scaling_ratio_frac_bits = 32;
tsc_aux_uret_slot = kvm_add_user_return_msr(MSR_TSC_AUX);
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 84a7500cd80c..e3a311b9ba34 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -7980,12 +7980,11 @@ static __init int hardware_setup(void)
if (!enable_apicv)
vmx_x86_ops.sync_pir_to_irr = NULL;
- if (cpu_has_vmx_tsc_scaling()) {
+ if (cpu_has_vmx_tsc_scaling())
kvm_has_tsc_control = true;
- kvm_max_tsc_scaling_ratio = KVM_VMX_TSC_MULTIPLIER_MAX;
- kvm_tsc_scaling_ratio_frac_bits = 48;
- }
+ kvm_max_tsc_scaling_ratio = KVM_VMX_TSC_MULTIPLIER_MAX;
+ kvm_tsc_scaling_ratio_frac_bits = 48;
kvm_has_bus_lock_exit = cpu_has_vmx_bus_lock_detection();
set_bit(0, vmx_vpid_bitmap); /* 0 is reserved for host */
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index ba920e537ddf..9c27239f987f 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -11631,10 +11631,8 @@ int kvm_arch_hardware_setup(void *opaque)
u64 max = min(0x7fffffffULL,
__scale_tsc(kvm_max_tsc_scaling_ratio, tsc_khz));
kvm_max_guest_tsc_khz = max;
-
- kvm_default_tsc_scaling_ratio = 1ULL << kvm_tsc_scaling_ratio_frac_bits;
}
-
+ kvm_default_tsc_scaling_ratio = 1ULL << kvm_tsc_scaling_ratio_frac_bits;
kvm_init_msr_list();
return 0;
}
--
2.26.3
next prev parent reply other threads:[~2022-03-22 17:25 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-22 17:24 [PATCH 0/8] SVM fixes + refactoring Maxim Levitsky
2022-03-22 17:24 ` [PATCH 1/8] KVM: x86: avoid loading a vCPU after .vm_destroy was called Maxim Levitsky
2022-03-30 0:27 ` Sean Christopherson
2022-03-30 12:07 ` Paolo Bonzini
2022-04-28 5:47 ` Maxim Levitsky
2022-03-22 17:24 ` [PATCH 2/8] KVM: x86: SVM: use vmcb01 in avic_init_vmcb and init_vmcb Maxim Levitsky
2022-03-24 18:12 ` Paolo Bonzini
2022-03-27 15:15 ` Maxim Levitsky
2022-03-22 17:24 ` [PATCH 3/8] kvm: x86: SVM: use vmcb* instead of svm->vmcb where it makes sense Maxim Levitsky
2022-03-22 17:24 ` [PATCH 4/8] KVM: x86: SVM: fix avic spec based definitions again Maxim Levitsky
2022-03-22 17:24 ` [PATCH 5/8] KVM: x86: SVM: move tsc ratio definitions to svm.h Maxim Levitsky
2022-03-22 17:24 ` [PATCH 6/8] kvm: x86: SVM: remove unused defines Maxim Levitsky
2022-03-22 17:24 ` Maxim Levitsky [this message]
2022-03-22 17:24 ` [PATCH 8/8] KVM: x86: SVM: remove vgif_enabled() Maxim Levitsky
2022-03-30 0:20 ` Sean Christopherson
2022-03-30 12:08 ` Paolo Bonzini
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