[patch 138/149] KVM: VMX: enable VMXON check with SMX enabled (Intel TXT)

Greg KH
2010-07-01T18:27:31Z

2.6.32-stable review patch. If anyone has any objections, please let us know.

------------------

From: Shane Wang <shane.wang@intel.com>

Per document, for feature control MSR:

Bit 1 enables VMXON in SMX operation. If the bit is clear, execution
of VMXON in SMX operation causes a general-protection exception.
Bit 2 enables VMXON outside SMX operation. If the bit is clear, execution
of VMXON outside SMX operation causes a general-protection exception.

This patch is to enable this kind of check with SMX for VMXON in KVM.

Signed-off-by: Shane Wang <shane.wang@intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
(cherry picked from commit cafd66595d92591e4bd25c3904e004fc6f897e2d)
---
arch/x86/include/asm/msr-index.h | 5 +++--
arch/x86/kernel/tboot.c | 1 +
arch/x86/kvm/vmx.c | 32 +++++++++++++++++++++-----------
include/linux/tboot.h | 1 +
4 files changed, 26 insertions(+), 13 deletions(-)

--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -198,8 +198,9 @@
#define MSR_IA32_EBL_CR_POWERON 0x0000002a
#define MSR_IA32_FEATURE_CONTROL 0x0000003a

-#define FEATURE_CONTROL_LOCKED (1<<0)
-#define FEATURE_CONTROL_VMXON_ENABLED (1<<2)
+#define FEATURE_CONTROL_LOCKED (1<<0)
+#define FEATURE_CONTROL_VMXON_ENABLED_INSIDE_SMX (1<<1)
+#define FEATURE_CONTROL_VMXON_ENABLED_OUTSIDE_SMX (1<<2)

#define MSR_IA32_APICBASE 0x0000001b
#define MSR_IA32_APICBASE_BSP (1<<8)
--- a/arch/x86/kernel/tboot.c
+++ b/arch/x86/kernel/tboot.c
@@ -46,6 +46,7 @@

/* Global pointer to shared data; NULL means no measured launch. */
struct tboot *tboot __read_mostly;
+EXPORT_SYMBOL(tboot);

/* timeout for APs (in secs) to enter wait-for-SIPI state during shutdown */
#define AP_WAIT_TIMEOUT 1
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -26,6 +26,7 @@
#include <linux/sched.h>
#include <linux/moduleparam.h>
#include <linux/ftrace_event.h>
+#include <linux/tboot.h>
#include "kvm_cache_regs.h"
#include "x86.h"

@@ -1140,9 +1141,16 @@ static __init int vmx_disabled_by_bios(v
u64 msr;

rdmsrl(MSR_IA32_FEATURE_CONTROL, msr);
- return (msr & (FEATURE_CONTROL_LOCKED |
- FEATURE_CONTROL_VMXON_ENABLED))
- == FEATURE_CONTROL_LOCKED;
+ if (msr & FEATURE_CONTROL_LOCKED) {
+ if (!(msr & FEATURE_CONTROL_VMXON_ENABLED_INSIDE_SMX)
+ && tboot_enabled())
+ return 1;
+ if (!(msr & FEATURE_CONTROL_VMXON_ENABLED_OUTSIDE_SMX)
+ && !tboot_enabled())
+ return 1;
+ }
+
+ return 0;
/* locked but not enabled */
}

@@ -1150,18 +1158,20 @@ static void hardware_enable(void *garbag
{
int cpu = raw_smp_processor_id();
u64 phys_addr = __pa(per_cpu(vmxarea, cpu));
- u64 old;
+ u64 old, test_bits;

INIT_LIST_HEAD(&per_cpu(vcpus_on_cpu, cpu));
rdmsrl(MSR_IA32_FEATURE_CONTROL, old);
- if ((old & (FEATURE_CONTROL_LOCKED |
- FEATURE_CONTROL_VMXON_ENABLED))
- != (FEATURE_CONTROL_LOCKED |
- FEATURE_CONTROL_VMXON_ENABLED))
+
+ test_bits = FEATURE_CONTROL_LOCKED;
+ test_bits |= FEATURE_CONTROL_VMXON_ENABLED_OUTSIDE_SMX;
+ if (tboot_enabled())
+ test_bits |= FEATURE_CONTROL_VMXON_ENABLED_INSIDE_SMX;
+
+ if ((old & test_bits) != test_bits) {
/* enable and lock */
- wrmsrl(MSR_IA32_FEATURE_CONTROL, old |
- FEATURE_CONTROL_LOCKED |
- FEATURE_CONTROL_VMXON_ENABLED);
+ wrmsrl(MSR_IA32_FEATURE_CONTROL, old | test_bits);
+ }
write_cr4(read_cr4() | X86_CR4_VMXE); /* FIXME: not cpu hotplug safe */
asm volatile (ASM_VMX_VMXON_RAX
: : "a"(&phys_addr), "m"(phys_addr)
--- a/include/linux/tboot.h
+++ b/include/linux/tboot.h
@@ -150,6 +150,7 @@ extern int tboot_force_iommu(void);

#else

+#define tboot_enabled() 0
#define tboot_probe() do { } while (0)
#define tboot_shutdown(shutdown_type) do { } while (0)
#define tboot_sleep(sleep_state, pm1a_control, pm1b_control) \