[GIT PULL] x86/cpu changes for v4.5

From: Ingo Molnar
Date: Mon Jan 11 2016 - 09:58:46 EST

Linus,

Please pull the latest x86-cpu-for-linus git tree from:

git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86-cpu-for-linus

# HEAD: 0007bccc3cfd1e69deb0fd73ccc426b4cedb061d x86: Replace RDRAND forced-reseed with simple sanity check

The main changes in this cycle were:

- Improved CPU ID handling code and related enhancements (Borislav Petkov)

- RDRAND fix (Len Brown)

Thanks,

Ingo

------------------>
Borislav Petkov (5):
x86/cpu: Unify CPU family, model, stepping calculation
kvm: Add accessors for guest CPU's family, model, stepping
x86/cpu/amd, kvm: Satisfy guest kernel reads of IC_CFG MSR
x86/cpu: Fix MSR value truncation issue
x86/MSR: Chop off lower 32-bit value

Len Brown (1):
x86: Replace RDRAND forced-reseed with simple sanity check


arch/x86/include/asm/cpu.h | 3 +++
arch/x86/include/asm/microcode.h | 39 +++++++----------------------------
arch/x86/include/asm/msr-index.h | 1 +
arch/x86/include/asm/msr.h | 2 +-
arch/x86/kernel/cpu/amd.c | 4 ++--
arch/x86/kernel/cpu/common.c | 13 ++++--------
arch/x86/kernel/cpu/microcode/core.c | 12 +++++------
arch/x86/kernel/cpu/microcode/intel.c | 16 ++++++--------
arch/x86/kernel/cpu/rdrand.c | 25 +++++++++++-----------
arch/x86/kvm/cpuid.h | 34 ++++++++++++++++++++++++++++++
arch/x86/kvm/svm.c | 17 +++++++++++++++
arch/x86/lib/Makefile | 2 +-
arch/x86/lib/cpu.c | 35 +++++++++++++++++++++++++++++++
13 files changed, 129 insertions(+), 74 deletions(-)
create mode 100644 arch/x86/lib/cpu.c

diff --git a/arch/x86/include/asm/cpu.h b/arch/x86/include/asm/cpu.h
index bf2caa1dedc5..678637ad7476 100644
--- a/arch/x86/include/asm/cpu.h
+++ b/arch/x86/include/asm/cpu.h
@@ -36,4 +36,7 @@ extern int _debug_hotplug_cpu(int cpu, int action);

int mwait_usable(const struct cpuinfo_x86 *);

+unsigned int x86_family(unsigned int sig);
+unsigned int x86_model(unsigned int sig);
+unsigned int x86_stepping(unsigned int sig);
#endif /* _ASM_X86_CPU_H */
diff --git a/arch/x86/include/asm/microcode.h b/arch/x86/include/asm/microcode.h
index 34e62b1dcfce..1e1b07a5a738 100644
--- a/arch/x86/include/asm/microcode.h
+++ b/arch/x86/include/asm/microcode.h
@@ -1,6 +1,7 @@
#ifndef _ASM_X86_MICROCODE_H
#define _ASM_X86_MICROCODE_H

+#include <asm/cpu.h>
#include <linux/earlycpio.h>

#define native_rdmsr(msr, val1, val2) \
@@ -95,14 +96,14 @@ static inline void __exit exit_amd_microcode(void) {}

/*
* In early loading microcode phase on BSP, boot_cpu_data is not set up yet.
- * x86_vendor() gets vendor id for BSP.
+ * x86_cpuid_vendor() gets vendor id for BSP.
*
* In 32 bit AP case, accessing boot_cpu_data needs linear address. To simplify
- * coding, we still use x86_vendor() to get vendor id for AP.
+ * coding, we still use x86_cpuid_vendor() to get vendor id for AP.
*
- * x86_vendor() gets vendor information directly from CPUID.
+ * x86_cpuid_vendor() gets vendor information directly from CPUID.
*/
-static inline int x86_vendor(void)
+static inline int x86_cpuid_vendor(void)
{
u32 eax = 0x00000000;
u32 ebx, ecx = 0, edx;
@@ -118,40 +119,14 @@ static inline int x86_vendor(void)
return X86_VENDOR_UNKNOWN;
}

-static inline unsigned int __x86_family(unsigned int sig)
-{
- unsigned int x86;
-
- x86 = (sig >> 8) & 0xf;
-
- if (x86 == 0xf)
- x86 += (sig >> 20) & 0xff;
-
- return x86;
-}
-
-static inline unsigned int x86_family(void)
+static inline unsigned int x86_cpuid_family(void)
{
u32 eax = 0x00000001;
u32 ebx, ecx = 0, edx;

native_cpuid(&eax, &ebx, &ecx, &edx);

- return __x86_family(eax);
-}
-
-static inline unsigned int x86_model(unsigned int sig)
-{
- unsigned int x86, model;
-
- x86 = __x86_family(sig);
-
- model = (sig >> 4) & 0xf;
-
- if (x86 == 0x6 || x86 == 0xf)
- model += ((sig >> 16) & 0xf) << 4;
-
- return model;
+ return x86_family(eax);
}

#ifdef CONFIG_MICROCODE
diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
index 690b4027e17c..b05402ef3b84 100644
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -321,6 +321,7 @@
#define MSR_F15H_PERF_CTR 0xc0010201
#define MSR_F15H_NB_PERF_CTL 0xc0010240
#define MSR_F15H_NB_PERF_CTR 0xc0010241
+#define MSR_F15H_IC_CFG 0xc0011021

/* Fam 10h MSRs */
#define MSR_FAM10H_MMIO_CONF_BASE 0xc0010058
diff --git a/arch/x86/include/asm/msr.h b/arch/x86/include/asm/msr.h
index 77d8b284e4a7..86133827c75c 100644
--- a/arch/x86/include/asm/msr.h
+++ b/arch/x86/include/asm/msr.h
@@ -190,7 +190,7 @@ static inline void wrmsr(unsigned msr, unsigned low, unsigned high)

static inline void wrmsrl(unsigned msr, u64 val)
{
- native_write_msr(msr, (u32)val, (u32)(val >> 32));
+ native_write_msr(msr, (u32)(val & 0xffffffffULL), (u32)(val >> 32));
}

/* wrmsr with exception handling */
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index a8816b325162..e229640c19ab 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -678,9 +678,9 @@ static void init_amd_bd(struct cpuinfo_x86 *c)
* Disable it on the affected CPUs.
*/
if ((c->x86_model >= 0x02) && (c->x86_model < 0x20)) {
- if (!rdmsrl_safe(0xc0011021, &value) && !(value & 0x1E)) {
+ if (!rdmsrl_safe(MSR_F15H_IC_CFG, &value) && !(value & 0x1E)) {
value |= 0x1E;
- wrmsrl_safe(0xc0011021, value);
+ wrmsrl_safe(MSR_F15H_IC_CFG, value);
}
}
}
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index c2b7522cbf35..105da8df87ae 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -581,14 +581,9 @@ void cpu_detect(struct cpuinfo_x86 *c)
u32 junk, tfms, cap0, misc;

cpuid(0x00000001, &tfms, &misc, &junk, &cap0);
- c->x86 = (tfms >> 8) & 0xf;
- c->x86_model = (tfms >> 4) & 0xf;
- c->x86_mask = tfms & 0xf;
-
- if (c->x86 == 0xf)
- c->x86 += (tfms >> 20) & 0xff;
- if (c->x86 >= 0x6)
- c->x86_model += ((tfms >> 16) & 0xf) << 4;
+ c->x86 = x86_family(tfms);
+ c->x86_model = x86_model(tfms);
+ c->x86_mask = x86_stepping(tfms);

if (cap0 & (1<<19)) {
c->x86_clflush_size = ((misc >> 8) & 0xff) * 8;
@@ -1185,7 +1180,7 @@ void syscall_init(void)
* They both write to the same internal register. STAR allows to
* set CS/DS but only a 32bit target. LSTAR sets the 64bit rip.
*/
- wrmsrl(MSR_STAR, ((u64)__USER32_CS)<<48 | ((u64)__KERNEL_CS)<<32);
+ wrmsr(MSR_STAR, 0, (__USER32_CS << 16) | __KERNEL_CS);
wrmsrl(MSR_LSTAR, (unsigned long)entry_SYSCALL_64);

#ifdef CONFIG_IA32_EMULATION
diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c
index 7fc27f1cca58..3aaffb601c91 100644
--- a/arch/x86/kernel/cpu/microcode/core.c
+++ b/arch/x86/kernel/cpu/microcode/core.c
@@ -129,8 +129,8 @@ void __init load_ucode_bsp(void)
if (!have_cpuid_p())
return;

- vendor = x86_vendor();
- family = x86_family();
+ vendor = x86_cpuid_vendor();
+ family = x86_cpuid_family();

switch (vendor) {
case X86_VENDOR_INTEL:
@@ -165,8 +165,8 @@ void load_ucode_ap(void)
if (!have_cpuid_p())
return;

- vendor = x86_vendor();
- family = x86_family();
+ vendor = x86_cpuid_vendor();
+ family = x86_cpuid_family();

switch (vendor) {
case X86_VENDOR_INTEL:
@@ -206,8 +206,8 @@ void reload_early_microcode(void)
{
int vendor, family;

- vendor = x86_vendor();
- family = x86_family();
+ vendor = x86_cpuid_vendor();
+ family = x86_cpuid_family();

switch (vendor) {
case X86_VENDOR_INTEL:
diff --git a/arch/x86/kernel/cpu/microcode/intel.c b/arch/x86/kernel/cpu/microcode/intel.c
index ce47402eb2f9..ee81c544ee0d 100644
--- a/arch/x86/kernel/cpu/microcode/intel.c
+++ b/arch/x86/kernel/cpu/microcode/intel.c
@@ -145,10 +145,10 @@ matching_model_microcode(struct microcode_header_intel *mc_header,
int ext_sigcount, i;
struct extended_signature *ext_sig;

- fam = __x86_family(sig);
+ fam = x86_family(sig);
model = x86_model(sig);

- fam_ucode = __x86_family(mc_header->sig);
+ fam_ucode = x86_family(mc_header->sig);
model_ucode = x86_model(mc_header->sig);

if (fam == fam_ucode && model == model_ucode)
@@ -163,7 +163,7 @@ matching_model_microcode(struct microcode_header_intel *mc_header,
ext_sigcount = ext_header->count;

for (i = 0; i < ext_sigcount; i++) {
- fam_ucode = __x86_family(ext_sig->sig);
+ fam_ucode = x86_family(ext_sig->sig);
model_ucode = x86_model(ext_sig->sig);

if (fam == fam_ucode && model == model_ucode)
@@ -365,7 +365,7 @@ static int collect_cpu_info_early(struct ucode_cpu_info *uci)
native_cpuid(&eax, &ebx, &ecx, &edx);
csig.sig = eax;

- family = __x86_family(csig.sig);
+ family = x86_family(csig.sig);
model = x86_model(csig.sig);

if ((model >= 5) || (family > 6)) {
@@ -521,16 +521,12 @@ static bool __init load_builtin_intel_microcode(struct cpio_data *cp)
{
#ifdef CONFIG_X86_64
unsigned int eax = 0x00000001, ebx, ecx = 0, edx;
- unsigned int family, model, stepping;
char name[30];

native_cpuid(&eax, &ebx, &ecx, &edx);

- family = __x86_family(eax);
- model = x86_model(eax);
- stepping = eax & 0xf;
-
- sprintf(name, "intel-ucode/%02x-%02x-%02x", family, model, stepping);
+ sprintf(name, "intel-ucode/%02x-%02x-%02x",
+ x86_family(eax), x86_model(eax), x86_stepping(eax));

return get_builtin_firmware(cp, name);
#else
diff --git a/arch/x86/kernel/cpu/rdrand.c b/arch/x86/kernel/cpu/rdrand.c
index 136ac74dee82..819d94982e07 100644
--- a/arch/x86/kernel/cpu/rdrand.c
+++ b/arch/x86/kernel/cpu/rdrand.c
@@ -33,28 +33,27 @@ static int __init x86_rdrand_setup(char *s)
__setup("nordrand", x86_rdrand_setup);

/*
- * Force a reseed cycle; we are architecturally guaranteed a reseed
- * after no more than 512 128-bit chunks of random data. This also
- * acts as a test of the CPU capability.
+ * RDRAND has Built-In-Self-Test (BIST) that runs on every invocation.
+ * Run the instruction a few times as a sanity check.
+ * If it fails, it is simple to disable RDRAND here.
*/
-#define RESEED_LOOP ((512*128)/sizeof(unsigned long))
+#define SANITY_CHECK_LOOPS 8

void x86_init_rdrand(struct cpuinfo_x86 *c)
{
#ifdef CONFIG_ARCH_RANDOM
unsigned long tmp;
- int i, count, ok;
+ int i;

if (!cpu_has(c, X86_FEATURE_RDRAND))
- return; /* Nothing to do */
+ return;

- for (count = i = 0; i < RESEED_LOOP; i++) {
- ok = rdrand_long(&tmp);
- if (ok)
- count++;
+ for (i = 0; i < SANITY_CHECK_LOOPS; i++) {
+ if (!rdrand_long(&tmp)) {
+ clear_cpu_cap(c, X86_FEATURE_RDRAND);
+ printk_once(KERN_WARNING "rdrand: disabled\n");
+ return;
+ }
}
-
- if (count != RESEED_LOOP)
- clear_cpu_cap(c, X86_FEATURE_RDRAND);
#endif
}
diff --git a/arch/x86/kvm/cpuid.h b/arch/x86/kvm/cpuid.h
index 06332cb7e7d1..5d47e0d95ef1 100644
--- a/arch/x86/kvm/cpuid.h
+++ b/arch/x86/kvm/cpuid.h
@@ -2,6 +2,7 @@
#define ARCH_X86_KVM_CPUID_H

#include "x86.h"
+#include <asm/cpu.h>

int kvm_update_cpuid(struct kvm_vcpu *vcpu);
struct kvm_cpuid_entry2 *kvm_find_cpuid_entry(struct kvm_vcpu *vcpu,
@@ -170,4 +171,37 @@ static inline bool guest_cpuid_has_nrips(struct kvm_vcpu *vcpu)
}
#undef BIT_NRIPS

+static inline int guest_cpuid_family(struct kvm_vcpu *vcpu)
+{
+ struct kvm_cpuid_entry2 *best;
+
+ best = kvm_find_cpuid_entry(vcpu, 0x1, 0);
+ if (!best)
+ return -1;
+
+ return x86_family(best->eax);
+}
+
+static inline int guest_cpuid_model(struct kvm_vcpu *vcpu)
+{
+ struct kvm_cpuid_entry2 *best;
+
+ best = kvm_find_cpuid_entry(vcpu, 0x1, 0);
+ if (!best)
+ return -1;
+
+ return x86_model(best->eax);
+}
+
+static inline int guest_cpuid_stepping(struct kvm_vcpu *vcpu)
+{
+ struct kvm_cpuid_entry2 *best;
+
+ best = kvm_find_cpuid_entry(vcpu, 0x1, 0);
+ if (!best)
+ return -1;
+
+ return x86_stepping(best->eax);
+}
+
#endif
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 83a1c643f9a5..58b64c17c4a8 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -3053,6 +3053,23 @@ static int svm_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
case MSR_IA32_UCODE_REV:
msr_info->data = 0x01000065;
break;
+ case MSR_F15H_IC_CFG: {
+
+ int family, model;
+
+ family = guest_cpuid_family(vcpu);
+ model = guest_cpuid_model(vcpu);
+
+ if (family < 0 || model < 0)
+ return kvm_get_msr_common(vcpu, msr_info);
+
+ msr_info->data = 0;
+
+ if (family == 0x15 &&
+ (model >= 0x2 && model < 0x20))
+ msr_info->data = 0x1E;
+ }
+ break;
default:
return kvm_get_msr_common(vcpu, msr_info);
}
diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile
index f2587888d987..a501fa25da41 100644
--- a/arch/x86/lib/Makefile
+++ b/arch/x86/lib/Makefile
@@ -16,7 +16,7 @@ clean-files := inat-tables.c

obj-$(CONFIG_SMP) += msr-smp.o cache-smp.o

-lib-y := delay.o misc.o cmdline.o
+lib-y := delay.o misc.o cmdline.o cpu.o
lib-y += usercopy_$(BITS).o usercopy.o getuser.o putuser.o
lib-y += memcpy_$(BITS).o
lib-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem.o
diff --git a/arch/x86/lib/cpu.c b/arch/x86/lib/cpu.c
new file mode 100644
index 000000000000..aa417a97511c
--- /dev/null
+++ b/arch/x86/lib/cpu.c
@@ -0,0 +1,35 @@
+#include <linux/module.h>
+
+unsigned int x86_family(unsigned int sig)
+{
+ unsigned int x86;
+
+ x86 = (sig >> 8) & 0xf;
+
+ if (x86 == 0xf)
+ x86 += (sig >> 20) & 0xff;
+
+ return x86;
+}
+EXPORT_SYMBOL_GPL(x86_family);
+
+unsigned int x86_model(unsigned int sig)
+{
+ unsigned int fam, model;
+
+ fam = x86_family(sig);
+
+ model = (sig >> 4) & 0xf;
+
+ if (fam >= 0x6)
+ model += ((sig >> 16) & 0xf) << 4;
+
+ return model;
+}
+EXPORT_SYMBOL_GPL(x86_model);
+
+unsigned int x86_stepping(unsigned int sig)
+{
+ return sig & 0xf;
+}
+EXPORT_SYMBOL_GPL(x86_stepping);