Commit f185e05dce6f for kernel

commit f185e05dce6f170f83c4ba602e969b1c3c7a22e6
Author: Sean Christopherson <seanjc@google.com>
Date:   Fri May 1 13:22:32 2026 -0700

    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 <thomas.lendacky@amd.com>
    Reviewed-by: Michael Roth <michael.roth@amd.com>
    Signed-off-by: Sean Christopherson <seanjc@google.com>
    Message-ID: <20260501202250.2115252-8-seanjc@google.com>
    Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

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");