linux-kernel - [PATCH V2] KVM: SVM: Only dump VSMA to klog for debugging

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Message-Id: <20221104142220.469452-1-pgonda@google.com>
Date:   Fri,  4 Nov 2022 07:22:20 -0700
From:   Peter Gonda <pgonda@...gle.com>
To:     jarkko@...nel.org
Cc:     Peter Gonda <pgonda@...gle.com>,
        Sean Christopherson <seanjc@...gle.com>,
        Harald Hoyer <harald@...fian.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org,
        "H. Peter Anvin" <hpa@...or.com>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org, stable@...r.kernel.org
Subject: [PATCH V2] KVM: SVM: Only dump VSMA to klog for debugging

Explicitly print the VMSA dump at KERN_DEBUG log level, KERN_CONT uses
KERNEL_DEFAULT if the previous log line has a newline, i.e. if there's
nothing to continuing, and as a result the VMSA gets dumped when it
shouldn't.

The KERN_CONT documentation says it defaults back to KERNL_DEFAULT if the
previous log line has a newline. So switch from KERN_CONT to
print_hex_dump_debug().

Jarkko pointed this out in reference to the original patch. See:
https://lore.kernel.org/all/YuPMeWX4uuR1Tz3M@kernel.org/
print_hex_dump(KERN_DEBUG, ...) was pointed out there, but
print_hex_dump_debug() should similar.

Fixes: 6fac42f127b8 ("KVM: SVM: Dump Virtual Machine Save Area (VMSA) to klog")
Signed-off-by: Peter Gonda <pgonda@...gle.com>
Reviewed-by: Sean Christopherson <seanjc@...gle.com>
Cc: Jarkko Sakkinen <jarkko@...nel.org>
Cc: Harald Hoyer <harald@...fian.com>
Cc: Paolo Bonzini <pbonzini@...hat.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: Borislav Petkov <bp@...en8.de>
Cc: Dave Hansen <dave.hansen@...ux.intel.com>
Cc: x86@...nel.org
Cc: "H. Peter Anvin" <hpa@...or.com>
Cc: kvm@...r.kernel.org
Cc: linux-kernel@...r.kernel.org
Cc: stable@...r.kernel.org
---
 arch/x86/kvm/svm/sev.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index c0c9ed5e279cb..9b8db157cf773 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -605,7 +605,7 @@ static int sev_es_sync_vmsa(struct vcpu_svm *svm)
 	save->dr6  = svm->vcpu.arch.dr6;
 
 	pr_debug("Virtual Machine Save Area (VMSA):\n");
-	print_hex_dump(KERN_CONT, "", DUMP_PREFIX_NONE, 16, 1, save, sizeof(*save), false);
+	print_hex_dump_debug("", DUMP_PREFIX_NONE, 16, 1, save, sizeof(*save), false);
 
 	return 0;
 }
-- 
2.38.1.431.g37b22c650d-goog