linuxmsm/laptops-kernel
0
0
Fork 0
mirror of https://github.com/linux-msm/laptops-kernel.git synced 2026-08-13 14:19:53 -07:00
Code Issues Packages Projects Releases Wiki Activity

x86/apic: KVM: Use cpu_physical_id() to get APIC ID of running vCPU for AVIC

Browse Source 
Use cpu_physical_id() instead of default_cpu_present_to_apicid() when
getting the APIC ID of the pCPU on which a vCPU is running/loaded, as the
kernel has gone way off the rails if a vCPU is loaded on a pCPU that has
been physically removed from the system.  Even if the impossible were to
happen, the absolutely worst case scenario is that hardware will ring the
AIVC doorbell on the wrong pCPU, i.e. a severely broken system will
experience mild performance issues.

Kill off KVM's superfluous kvm_cpu_get_apicid() wrapper along with the
for-KVM export of default_cpu_present_to_apicid(), as they existed purely
for the wonky AVIC usage.

Cc: Kai Huang <kai.huang@intel.com>
Cc: Yosry Ahmed <yosry@kernel.org>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Acked-by: Naveen N Rao (AMD) <naveen@kernel.org>
Reviewed-by: Kai Huang <kai.huang@intel.com>
Reviewed-by: Yosry Ahmed <yosry@kernel.org>
Message-ID: <20260612185459.591892-1-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Sean Christopherson
2026-06-24 07:52:24 -04:00
committed by Paolo Bonzini
parent 02953418a1
commit 098e32cba3
3 changed files with 3 additions and 14 deletions
Download Patch File Download Diff File Expand all files Collapse all files
arch/x86/include/asm/kvm_host.h
-10
View File
@@ -2525,16 +2525,6 @@ static inline void kvm_arch_vcpu_unblocking(struct kvm_vcpu *vcpu)
kvm_x86_call(vcpu_unblocking)(vcpu);
}
static inline int kvm_cpu_get_apicid(int mps_cpu)
{
#ifdef CONFIG_X86_LOCAL_APIC
return default_cpu_present_to_apicid(mps_cpu);
#else
WARN_ON_ONCE(1);
return BAD_APICID;
#endif
}
int memslot_rmap_alloc(struct kvm_memory_slot *slot, unsigned long npages);
#define KVM_CLOCK_VALID_FLAGS \
arch/x86/kernel/apic/apic_common.c
-1
View File
@@ -26,7 +26,6 @@ u32 default_cpu_present_to_apicid(int mps_cpu)
else
return BAD_APICID;
}
EXPORT_SYMBOL_FOR_KVM(default_cpu_present_to_apicid);
/*
* Set up the logical destination ID when the APIC operates in logical
arch/x86/kvm/svm/avic.c
+3 -3
View File
@@ -460,8 +460,8 @@ void avic_ring_doorbell(struct kvm_vcpu *vcpu)
int cpu = READ_ONCE(vcpu->cpu);
if (cpu != get_cpu()) {
wrmsrq(MSR_AMD64_SVM_AVIC_DOORBELL, kvm_cpu_get_apicid(cpu));
trace_kvm_avic_doorbell(vcpu->vcpu_id, kvm_cpu_get_apicid(cpu));
wrmsrq(MSR_AMD64_SVM_AVIC_DOORBELL, cpu_physical_id(cpu));
trace_kvm_avic_doorbell(vcpu->vcpu_id, cpu_physical_id(cpu));
}
put_cpu();
}
@@ -1013,7 +1013,7 @@ static void __avic_vcpu_load(struct kvm_vcpu *vcpu, int cpu,
enum avic_vcpu_action action)
{
struct kvm_svm *kvm_svm = to_kvm_svm(vcpu->kvm);
int h_physical_id = kvm_cpu_get_apicid(cpu);
int h_physical_id = cpu_physical_id(cpu);
struct vcpu_svm *svm = to_svm(vcpu);
unsigned long flags;
u64 entry;