Commit 468c27ae authored by Tom Lendacky's avatar Tom Lendacky Committed by Sean Christopherson
Browse files

KVM: SVM: Add a mutex to dump_vmcb() to prevent concurrent output 



If multiple VMRUN instructions fail, resulting in calls to dump_vmcb(),
the output can become interleaved and it is impossible to identify which
line of output belongs to which VMCB. Add a mutex to dump_vmcb() so that
the output is serialized.

Signed-off-by: default avatarTom Lendacky <thomas.lendacky@amd.com>
Acked-by: default avatarBorislav Petkov (AMD) <bp@alien8.de>
Tested-by: default avatarKim Phillips <kim.phillips@amd.com>
Link: https://lore.kernel.org/r/a880678afd9488e1dd6017445802712f7c02cc6d.1742477213.git.thomas.lendacky@amd.com


Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
parent 0e6b677d

arch/x86/kvm/svm/svm.c

+5 −0
Original line number Diff line number Diff line
@@ -29,6 +29,7 @@ 
#include <linux/cc_platform.h>

#include <linux/smp.h>

#include <linux/string_choices.h>

#include <linux/mutex.h>



#include <asm/apic.h>

#include <asm/perf_event.h>
@@ -249,6 +250,8 @@ static unsigned long iopm_base; 


DEFINE_PER_CPU(struct svm_cpu_data, svm_data);



static DEFINE_MUTEX(vmcb_dump_mutex);



/*

 * Only MSR_TSC_AUX is switched via the user return hook.  EFER is switched via

 * the VMCB, and the SYSCALL/SYSENTER MSRs are handled by VMLOAD/VMSAVE.
@@ -3404,6 +3407,8 @@ static void dump_vmcb(struct kvm_vcpu *vcpu) 
		return;

	}



	guard(mutex)(&vmcb_dump_mutex);



	vm_type = sev_snp_guest(vcpu->kvm) ? "SEV-SNP" :

		  sev_es_guest(vcpu->kvm) ? "SEV-ES" :

		  sev_guest(vcpu->kvm) ? "SEV" : "SVM";