[Qemu-devel] [PATCH v2] fw/msr_feature_control: add support to set MSR_IA32_FEATURE_CONTROL

[Haozhong Zhang <haozhong.zhang@intel.com>]

OS usually expects BIOS to set certain bits in MSR_IA32_FEATURE_CONTROL
for some features (e.g. VMX and LMCE). QEMU provides a fw_cfg file
"etc/msr_feature_control" to advise bits that should be set in
MSR_IA32_FEATURE_CONTROL. If this file exists, SeaBIOS will set the
advised bits in that MSR.

Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com>
---
Changes in v2:
 * Call msr_feature_control_setup() before smp_setup().
 * Use wrmsr_smp() instead of wrmsr() on BSP.
 * Rename smp_mtrr and smp_mtrr_count to smp_msr and smp_msr_count
   as they are not only used for MTRR now.
---
 Makefile                     |  2 +-
 src/fw/msr_feature_control.c | 16 ++++++++++++++++
 src/fw/paravirt.c            |  3 ++-
 src/fw/smp.c                 | 20 ++++++++++----------
 src/util.h                   |  3 +++
 5 files changed, 32 insertions(+), 12 deletions(-)
 create mode 100644 src/fw/msr_feature_control.c

diff --git a/Makefile b/Makefile
index 4930b3a..f38a075 100644
--- a/Makefile
+++ b/Makefile
@@ -43,7 +43,7 @@ SRC32FLAT=$(SRCBOTH) post.c e820map.c malloc.c romfile.c x86.c optionroms.c \
     fw/paravirt.c fw/shadow.c fw/pciinit.c fw/smm.c fw/smp.c fw/mtrr.c fw/xen.c \
     fw/acpi.c fw/mptable.c fw/pirtable.c fw/smbios.c fw/romfile_loader.c \
     hw/virtio-ring.c hw/virtio-pci.c hw/virtio-blk.c hw/virtio-scsi.c \
-    hw/tpm_drivers.c
+    hw/tpm_drivers.c fw/msr_feature_control.c
 SRC32SEG=string.c output.c pcibios.c apm.c stacks.c hw/pci.c hw/serialio.c
 DIRS=src src/hw src/fw vgasrc
 
diff --git a/src/fw/msr_feature_control.c b/src/fw/msr_feature_control.c
new file mode 100644
index 0000000..5ddc051
--- /dev/null
+++ b/src/fw/msr_feature_control.c
@@ -0,0 +1,16 @@
+#include "util.h" // msr_feature_control_setup, wrmsr_smp
+#include "romfile.h" // romfile_find
+
+#define MSR_IA32_FEATURE_CONTROL 0x0000003a
+
+void msr_feature_control_setup(void)
+{
+    struct romfile_s *f = romfile_find("etc/msr_feature_control");
+    if (!f)
+        return;
+
+    u64 feature_control_bits;
+    f->copy(f, &feature_control_bits, sizeof(feature_control_bits));
+    if (feature_control_bits)
+        wrmsr_smp(MSR_IA32_FEATURE_CONTROL, feature_control_bits);
+}
diff --git a/src/fw/paravirt.c b/src/fw/paravirt.c
index 8ed4380..dbb3406 100644
--- a/src/fw/paravirt.c
+++ b/src/fw/paravirt.c
@@ -149,8 +149,9 @@ qemu_platform_setup(void)
     smm_device_setup();
     smm_setup();
 
-    // Initialize mtrr and smp
+    // Initialize mtrr, msr_feature_control and smp
     mtrr_setup();
+    msr_feature_control_setup();
     smp_setup();
 
     // Create bios tables
diff --git a/src/fw/smp.c b/src/fw/smp.c
index 579acdb..6e706e4 100644
--- a/src/fw/smp.c
+++ b/src/fw/smp.c
@@ -10,7 +10,7 @@
 #include "output.h" // dprintf
 #include "romfile.h" // romfile_loadint
 #include "stacks.h" // yield
-#include "util.h" // smp_setup
+#include "util.h" // smp_setup, msr_feature_control_setup
 #include "x86.h" // wrmsr
 
 #define APIC_ICR_LOW ((u8*)BUILD_APIC_ADDR + 0x300)
@@ -20,20 +20,20 @@
 
 #define APIC_ENABLED 0x0100
 
-static struct { u32 index; u64 val; } smp_mtrr[32];
-static u32 smp_mtrr_count;
+static struct { u32 index; u64 val; } smp_msr[32];
+static u32 smp_msr_count;
 
 void
 wrmsr_smp(u32 index, u64 val)
 {
     wrmsr(index, val);
-    if (smp_mtrr_count >= ARRAY_SIZE(smp_mtrr)) {
+    if (smp_msr_count >= ARRAY_SIZE(smp_msr)) {
         warn_noalloc();
         return;
     }
-    smp_mtrr[smp_mtrr_count].index = index;
-    smp_mtrr[smp_mtrr_count].val = val;
-    smp_mtrr_count++;
+    smp_msr[smp_msr_count].index = index;
+    smp_msr[smp_msr_count].val = val;
+    smp_msr_count++;
 }
 
 u32 MaxCountCPUs;
@@ -58,10 +58,10 @@ handle_smp(void)
     u8 apic_id = ebx>>24;
     dprintf(DEBUG_HDL_smp, "handle_smp: apic_id=%d\n", apic_id);
 
-    // MTRR setup
+    // MTRR and MSR_IA32_FEATURE_CONTROL setup
     int i;
-    for (i=0; i<smp_mtrr_count; i++)
-        wrmsr(smp_mtrr[i].index, smp_mtrr[i].val);
+    for (i=0; i<smp_msr_count; i++)
+        wrmsr(smp_msr[i].index, smp_msr[i].val);
 
     // Set bit on FoundAPICIDs
     FoundAPICIDs[apic_id/32] |= (1 << (apic_id % 32));
diff --git a/src/util.h b/src/util.h
index 7b41207..61877fa 100644
--- a/src/util.h
+++ b/src/util.h
@@ -103,6 +103,9 @@ int csm_bootprio_pci(struct pci_device *pci);
 // fw/mptable.c
 void mptable_setup(void);
 
+// fw/msr_feature_control.c
+void msr_feature_control_setup(void);
+
 // fw/mtrr.c
 void mtrr_setup(void);
 
-- 
2.9.0