Commit 5fea0c6c authored by Tom Lendacky's avatar Tom Lendacky Committed by Sean Christopherson
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KVM: SVM: Update dump_ghcb() to use the GHCB snapshot fields 



Commit 4e15a0dd ("KVM: SEV: snapshot the GHCB before accessing it")
updated the SEV code to take a snapshot of the GHCB before using it. But
the dump_ghcb() function wasn't updated to use the snapshot locations.
This results in incorrect output from dump_ghcb() for the "is_valid" and
"valid_bitmap" fields.

Update dump_ghcb() to use the proper locations.

Fixes: 4e15a0dd ("KVM: SEV: snapshot the GHCB before accessing it")
Signed-off-by: default avatarTom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: default avatarLiam Merwick <liam.merwick@oracle.com>
Link: https://lore.kernel.org/r/8f03878443681496008b1b37b7c4bf77a342b459.1745866531.git.thomas.lendacky@amd.com


[sean: add comment and snapshot qualifier]
Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
parent 20a6cff3

arch/x86/kvm/svm/sev.c

+19 −13
Original line number Diff line number Diff line
@@ -3173,9 +3173,14 @@ void sev_free_vcpu(struct kvm_vcpu *vcpu) 
		kvfree(svm->sev_es.ghcb_sa);

}



static u64 kvm_ghcb_get_sw_exit_code(struct vmcb_control_area *control)

{

	return (((u64)control->exit_code_hi) << 32) | control->exit_code;

}



static void dump_ghcb(struct vcpu_svm *svm)

{

	struct ghcb *ghcb = svm->sev_es.ghcb;

	struct vmcb_control_area *control = &svm->vmcb->control;

	unsigned int nbits;



	/* Re-use the dump_invalid_vmcb module parameter */
@@ -3184,18 +3189,24 @@ static void dump_ghcb(struct vcpu_svm *svm) 
		return;

	}



	nbits = sizeof(ghcb->save.valid_bitmap) * 8;

	nbits = sizeof(svm->sev_es.valid_bitmap) * 8;



	pr_err("GHCB (GPA=%016llx):\n", svm->vmcb->control.ghcb_gpa);

	/*

	 * Print KVM's snapshot of the GHCB values that were (unsuccessfully)

	 * used to handle the exit.  If the guest has since modified the GHCB

	 * itself, dumping the raw GHCB won't help debug why KVM was unable to

	 * handle the VMGEXIT that KVM observed.

	 */

	pr_err("GHCB (GPA=%016llx) snapshot:\n", svm->vmcb->control.ghcb_gpa);

	pr_err("%-20s%016llx is_valid: %u\n", "sw_exit_code",

	       ghcb->save.sw_exit_code, ghcb_sw_exit_code_is_valid(ghcb));

	       kvm_ghcb_get_sw_exit_code(control), kvm_ghcb_sw_exit_code_is_valid(svm));

	pr_err("%-20s%016llx is_valid: %u\n", "sw_exit_info_1",

	       ghcb->save.sw_exit_info_1, ghcb_sw_exit_info_1_is_valid(ghcb));

	       control->exit_info_1, kvm_ghcb_sw_exit_info_1_is_valid(svm));

	pr_err("%-20s%016llx is_valid: %u\n", "sw_exit_info_2",

	       ghcb->save.sw_exit_info_2, ghcb_sw_exit_info_2_is_valid(ghcb));

	       control->exit_info_2, kvm_ghcb_sw_exit_info_2_is_valid(svm));

	pr_err("%-20s%016llx is_valid: %u\n", "sw_scratch",

	       ghcb->save.sw_scratch, ghcb_sw_scratch_is_valid(ghcb));

	pr_err("%-20s%*pb\n", "valid_bitmap", nbits, ghcb->save.valid_bitmap);

	       svm->sev_es.sw_scratch, kvm_ghcb_sw_scratch_is_valid(svm));

	pr_err("%-20s%*pb\n", "valid_bitmap", nbits, svm->sev_es.valid_bitmap);

}



static void sev_es_sync_to_ghcb(struct vcpu_svm *svm)
@@ -3266,11 +3277,6 @@ static void sev_es_sync_from_ghcb(struct vcpu_svm *svm) 
	memset(ghcb->save.valid_bitmap, 0, sizeof(ghcb->save.valid_bitmap));

}



static u64 kvm_ghcb_get_sw_exit_code(struct vmcb_control_area *control)

{

	return (((u64)control->exit_code_hi) << 32) | control->exit_code;

}



static int sev_es_validate_vmgexit(struct vcpu_svm *svm)

{

	struct vmcb_control_area *control = &svm->vmcb->control;