[SeaBIOS] [PATCH] smm: ignore bits 16,18-31 of SMM revision ID
Paolo Bonzini
pbonzini at redhat.com
Wed May 6 12:38:29 CEST 2015
Bits 16-31 of the SMM revision ID are feature bits. We only need to
check that SMBASE relocation is supported, but do not care about other
features. In particular, this allows the SMM I/O instruction restart
feature to be present.
Signed-off-by: Paolo Bonzini <pbonzini at redhat.com>
---
src/fw/smm.c | 15 +++++++++++----
1 file changed, 11 insertions(+), 4 deletions(-)
diff --git a/src/fw/smm.c b/src/fw/smm.c
index dabc677..6cb484e 100644
--- a/src/fw/smm.c
+++ b/src/fw/smm.c
@@ -18,8 +18,14 @@
#include "util.h" // smm_setup
#include "x86.h" // wbinvd
-#define SMM_REV_I32 0x00020000
-#define SMM_REV_I64 0x00020064
+/*
+ * Check SMM state save area format (bits 0-15) and require support
+ * for SMBASE relocation.
+ */
+#define SMM_REV_MASK 0x0002ffff
+
+#define SMM_REV_I32 0x00020000
+#define SMM_REV_I64 0x00020064
struct smm_state {
union {
@@ -62,9 +68,10 @@ handle_smi(u16 cs)
if (smm == (void*)BUILD_SMM_INIT_ADDR) {
// relocate SMBASE to 0xa0000
- if (smm->cpu.i32.smm_rev == SMM_REV_I32) {
+ u32 rev = smm->cpu.i32.smm_rev & SMM_REV_MASK;
+ if (rev == SMM_REV_I32) {
smm->cpu.i32.smm_base = BUILD_SMM_ADDR;
- } else if (smm->cpu.i64.smm_rev == SMM_REV_I64) {
+ } else if (rev == SMM_REV_I64) {
smm->cpu.i64.smm_base = BUILD_SMM_ADDR;
} else {
warn_internalerror();
--
2.3.5
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