I don't think we need this patch. When SVM is disabled KVM will tell on
module load. Further with SVM-lock it will be possible to re-enable SVM
even if it was disabled by BIOS using a key. In this case the user of
SVM has to clear the capability bit you set in this patch for all cpus.
On Sat, Sep 22, 2007 at 12:32:18AM +0200, Andi Kleen wrote:
>
> Also allow to set svm lock.
>
> TBD double check, documentation, i386 support
>
> Signed-off-by: Andi Kleen <[email protected]>
>
> ---
> arch/x86_64/kernel/setup.c | 25 +++++++++++++++++++++++--
> include/asm-i386/cpufeature.h | 1 +
> include/asm-i386/msr-index.h | 3 +++
> 3 files changed, 27 insertions(+), 2 deletions(-)
>
> Index: linux/arch/x86_64/kernel/setup.c
> ===================================================================
> --- linux.orig/arch/x86_64/kernel/setup.c
> +++ linux/arch/x86_64/kernel/setup.c
> @@ -565,7 +565,7 @@ static void __cpuinit early_init_amd(str
>
> static void __cpuinit init_amd(struct cpuinfo_x86 *c)
> {
> - unsigned level;
> + unsigned level, flags, dummy;
>
> #ifdef CONFIG_SMP
> unsigned long value;
> @@ -634,7 +634,28 @@ static void __cpuinit init_amd(struct cp
> /* Family 10 doesn't support C states in MWAIT so don't use it */
> if (c->x86 == 0x10 && !force_mwait)
> clear_bit(X86_FEATURE_MWAIT, &c->x86_capability);
> +
> + if (c->x86 >= 0xf && c->x86 <= 0x11 &&
> + !rdmsr_safe(MSR_VM_CR, &flags, &dummy) &&
> + (flags & 0x18))
> + set_bit(X86_FEATURE_VIRT_DISABLED, &c->x86_capability);
> +}
> +
> +static int enable_svm_lock(char *s)
> +{
> + if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD &&
> + boot_cpu_data.x86 >= 0xf && boot_cpu_data.x86 <= 0x11) {
> + unsigned a,b;
> + if (rdmsr_safe(MSR_VM_CR, &a, &b))
> + return 0;
> + a |= (1 << 3); /* set SVM lock */
> + if (!wrmsr_safe(MSR_VM_CR, &a, &b))
> + return 1;
> + }
> + printk(KERN_ERR "CPU does not support svm_lock\n");
> + return 0;
> }
> +__setup("svm_lock", enable_svm_lock);
>
> static void __cpuinit detect_ht(struct cpuinfo_x86 *c)
> {
> @@ -985,7 +1006,7 @@ static int show_cpuinfo(struct seq_file
> NULL, NULL, NULL, NULL,
> "constant_tsc", "up", NULL, "arch_perfmon",
> "pebs", "bts", NULL, "sync_rdtsc",
> - "rep_good", NULL, NULL, NULL, NULL, NULL, NULL, NULL,
> + "rep_good", "virtualization_bios_disabled", NULL, NULL, NULL, NULL, NULL, NULL,
> NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
>
> /* Intel-defined (#2) */
> Index: linux/include/asm-i386/cpufeature.h
> ===================================================================
> --- linux.orig/include/asm-i386/cpufeature.h
> +++ linux/include/asm-i386/cpufeature.h
> @@ -82,6 +82,7 @@
> /* 14 free */
> #define X86_FEATURE_SYNC_RDTSC (3*32+15) /* RDTSC synchronizes the CPU */
> #define X86_FEATURE_REP_GOOD (3*32+16) /* rep microcode works well on this CPU */
> +#define X86_FEATURE_VIRT_DISABLED (3*32+17) /* Hardware virt. BIOS disabled */
>
> /* Intel-defined CPU features, CPUID level 0x00000001 (ecx), word 4 */
> #define X86_FEATURE_XMM3 (4*32+ 0) /* Streaming SIMD Extensions-3 */
> Index: linux/include/asm-i386/msr-index.h
> ===================================================================
> --- linux.orig/include/asm-i386/msr-index.h
> +++ linux/include/asm-i386/msr-index.h
> @@ -98,6 +98,9 @@
> #define K8_MTRRFIXRANGE_DRAM_MODIFY 0x00080000 /* MtrrFixDramModEn bit */
> #define K8_MTRR_RDMEM_WRMEM_MASK 0x18181818 /* Mask: RdMem|WrMem */
>
> +/* SVM */
> +#define MSR_VM_CR 0xc0010114
> +
> /* K7 MSRs */
> #define MSR_K7_EVNTSEL0 0xc0010000
> #define MSR_K7_PERFCTR0 0xc0010004
> -
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