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Remove code that enables/disables VMX in coreboot on chromebooks. 

There are several reasons for this:
1. It's a core setting, not a platform setting, which is bizarre. But,
we disable vmx via an SMI, and that only happens on core 0.
Hence, the code did not correctly make the same settings on all cores-
one had them disabled, the others were in an unknown state.
When (e.g.) kvm started on a vmx-enabled core, then moved to a
vmx-disabled core, the processor would reset *very* quickly.
Changing this would be messy.

2. On the CPU on link, there is something about trying to set the lock
bit that is getting a GPF.

3. It's the wrong place and time to set it. Once controlled, they can't
be changed in the kernel. The kernel is what should control this
feature, not the BIOS, as we have learned time and time again. If
somebody is in as root and can start a VM, you have a lot more to
worry about than someone starting a guest virtual machine.

Change-Id: I4f36093f1b68207251584066ccb9a6bcfeec767e
Signed-off-by: Ronald G. Minnich <rminnich@chromium.org>
Reviewed-on: http://review.coreboot.org/1276
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
This commit is contained in:
Ronald G. Minnich 2012-06-05 14:08:10 -07:00 committed by Ronald G. Minnich
parent 28190ce4de
commit 305b19dd7a
3 changed files with 0 additions and 43 deletions
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4
src/cpu/intel/model_206ax/Kconfig
View File

@ -21,10 +21,6 @@ config SMM_TSEG_SIZE
hex
default 0x800000
config ENABLE_VMX
bool "Enable VMX for virtualization"
default n
endif
if CPU_INTEL_MODEL_206AX

1
src/cpu/intel/model_206ax/finalize.c
View File

@ -43,7 +43,6 @@ static void msr_set_bit(unsigned reg, unsigned bit)
void intel_model_206ax_finalize_smm(void)
{
msr_set_bit(IA32_FEATURE_CONTROL, 0);
msr_set_bit(MSR_PMG_CST_CONFIG_CONTROL, 15);
/* Lock AES-NI only if supported */

38
src/cpu/intel/model_206ax/model_206ax_init.c
View File

@ -119,41 +119,6 @@ static const uint32_t microcode_updates[] = {
#include "x06_microcode.h"
};
static void enable_vmx(void)
{
struct cpuid_result regs;
msr_t msr;
int enable = CONFIG_ENABLE_VMX;
msr = rdmsr(IA32_FEATURE_CONTROL);
if (msr.lo & (1 << 0)) {
printk(BIOS_ERR, "VMX is locked, so enable_vmx will do nothing\n");
/* VMX locked. If we set it again we get an illegal
* instruction
*/
return;
}
regs = cpuid(1);
printk(BIOS_DEBUG, "%s VMX\n", enable ? "Enabling" : "Disabling");
if (regs.ecx & CPUID_VMX) {
if (enable)
msr.lo |= (1 << 2);
else
msr.lo &= ~(1 << 2);
if (regs.ecx & CPUID_SMX) {
if (enable)
msr.lo |= (1 << 1);
else
msr.lo &= ~(1 << 1);
}
}
wrmsr(IA32_FEATURE_CONTROL, msr);
}
/* Convert time in seconds to POWER_LIMIT_1_TIME MSR value */
static const u8 power_limit_time_sec_to_msr[] = {
[0] = 0x00,
@ -456,9 +421,6 @@ static void model_206ax_init(device_t cpu)
enable_lapic_tpr();
setup_lapic();
/* Enable virtualization if enabled in CMOS */
enable_vmx();
/* Configure C States */
configure_c_states();