target/i386: suppress CPUID leaves not defined by the CPU vendor

Currently all built-in CPUs report cache information via CPUID leaves 2
and 4, but these have never been defined for AMD. In the case of
SEV-SNP this can cause issues with CPUID enforcement. Address this by
allowing CPU types to suppress these via a new "x-vendor-cpuid-only"
CPU property, which is true by default, but switched off for older
machine types to maintain compatibility.

Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Richard Henderson <richard.henderson@linaro.org>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: zhenwei pi <pizhenwei@bytedance.com>
Suggested-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Michael Roth <michael.roth@amd.com>
Message-Id: <20210708003623.18665-1-michael.roth@amd.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index 8e1220db72..aa79c5e0e6 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -98,6 +98,7 @@ GlobalProperty pc_compat_6_0[] = {
     { "qemu64" "-" TYPE_X86_CPU, "family", "6" },
     { "qemu64" "-" TYPE_X86_CPU, "model", "6" },
     { "qemu64" "-" TYPE_X86_CPU, "stepping", "3" },
+    { TYPE_X86_CPU, "x-vendor-cpuid-only", "off" },
 };
 const size_t pc_compat_6_0_len = G_N_ELEMENTS(pc_compat_6_0);