From f185e05dce6f170f83c4ba602e969b1c3c7a22e6 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Fri, 1 May 2026 13:22:32 -0700 Subject: [PATCH] KVM: SEV: WARN if KVM attempts to setup scratch area with min_len==0 Now that all paths in KVM properly validate the length needed for the scratch area, and are guaranteed to pass in a non-zero length, WARN if KVM attempts to configured the scratch area with min_len==0 to guard against future bugs. Cc: stable@vger.kernel.org Reviewed-by: Tom Lendacky Reviewed-by: Michael Roth Signed-off-by: Sean Christopherson Message-ID: <20260501202250.2115252-8-seanjc@google.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/svm/sev.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index 6072fecfe994..a3e85348ace9 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -3669,6 +3669,9 @@ static int setup_vmgexit_scratch(struct vcpu_svm *svm, bool sync, u64 min_len) u64 scratch_gpa_beg, scratch_gpa_end; void *scratch_va; + if (WARN_ON_ONCE(!min_len)) + goto e_scratch; + scratch_gpa_beg = svm->sev_es.sw_scratch; if (!scratch_gpa_beg) { pr_err("vmgexit: scratch gpa not provided\n");