target/i386: Export GDS_NO bit to guests

Gather Data Sampling (GDS) is a side-channel attack using Gather
instructions. Some Intel processors will set ARCH_CAP_GDS_NO bit in
MSR IA32_ARCH_CAPABILITIES to report that they are not vulnerable to
GDS.

Make this bit available to guests.

Closes: https://lore.kernel.org/qemu-devel/CAMGffEmG6TNq0n3+4OJAgXc8J0OevY60KHZekXCBs3LoK9vehA@mail.gmail.com/
Reported-by: Jack Wang <jinpu.wang@ionos.com>
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Tested-by: Jack Wang <jinpu.wang@ionos.com>
Tested-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Message-ID: <fde42d81ce454477ca8e27d5429a190b7366fe86.1692074650.git.pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index d48607b..f9e51a9 100644 (file)
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -1155,7 +1155,7 @@ FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
             NULL, "sbdr-ssdp-no", "fbsdp-no", "psdp-no",
             NULL, "fb-clear", NULL, NULL,
             NULL, NULL, NULL, NULL,
-            "pbrsb-no", NULL, NULL, NULL,
+            "pbrsb-no", NULL, "gds-no", NULL,
             NULL, NULL, NULL, NULL,
         },
         .msr = {