Some features (Intel MKTME, AMD SME) may reduce number of effectively
available physical address bits. We adjust x86_phys_bits accordingly.
But if get_cpu_cap() got called more than one time we may lose this
information.
That's exactly what happens in setup_pku(): it gets called after
detect_tme() and x86_phys_bits gets overwritten.
Add x86_phys_bits_adj which stores by how many bits we should reduce
x86_phys_bits comparing to what CPUID returns.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Reported-by: Kai Huang <kai.huang@xxxxxxxxxxxxxxx>
Fixes: cb06d8e3d020 ("x86/tme: Detect if TME and MKTME is activated by BIOS")
---
arch/x86/include/asm/processor.h | 1 +
arch/x86/kernel/cpu/amd.c | 3 ++-
arch/x86/kernel/cpu/common.c | 14 ++++++++++++++
arch/x86/kernel/cpu/intel.c | 1 +
4 files changed, 18 insertions(+), 1 deletion(-)
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index b0ccd4847a58..1250547c8eb7 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -98,6 +98,7 @@ struct cpuinfo_x86 {
#endif
__u8 x86_virt_bits;
__u8 x86_phys_bits;
+ __u8 x86_phys_bits_adj;
/* CPUID returned core id bits: */
__u8 x86_coreid_bits;
__u8 cu_id;
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index 12bc0a1139da..4d0ec075f99e 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -583,7 +583,8 @@ static void early_detect_mem_encrypt(struct cpuinfo_x86 *c)
* will be a value above 32-bits this is still done for
* CONFIG_X86_32 so that accurate values are reported.
*/
- c->x86_phys_bits -= (cpuid_ebx(0x8000001f) >> 6) & 0x3f;
+ c->x86_phys_bits_adj = (cpuid_ebx(0x8000001f) >> 6) & 0x3f;
+ c->x86_phys_bits -= c->x86_phys_bits_adj;
if (IS_ENABLED(CONFIG_X86_32))
goto clear_all;
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 348cf4821240..d2e3dd827691 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -854,6 +854,20 @@ void get_cpu_cap(struct cpuinfo_x86 *c)
c->x86_virt_bits = (eax >> 8) & 0xff;
c->x86_phys_bits = eax & 0xff;
c->x86_capability[CPUID_8000_0008_EBX] = ebx;
+
+ /*
+ * Some features (Intel MKTME, AMD SME) may reduce number
+ * of effectively available physical address bits.
+ *
+ * We adjust x86_phys_bits accordingly.
+ *
+ * But if get_cpu_cap() got called more than one time we
+ * may lose this information.
+ *
+ * x86_phys_bits_adj stores by how many bits we should
+ * reduce x86_phys_bits comparing to what CPUID returns.
+ */
+ c->x86_phys_bits -= c->x86_phys_bits_adj;
}
#ifdef CONFIG_X86_32
else if (cpu_has(c, X86_FEATURE_PAE) || cpu_has(c, X86_FEATURE_PSE36))
diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index fd379358c58d..801c2e42b87d 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -623,6 +623,7 @@ static void detect_tme(struct cpuinfo_x86 *c)
* Let's update cpuinfo_x86::x86_phys_bits to reflect the fact.
*/
c->x86_phys_bits -= keyid_bits;
+ c->x86_phys_bits_adj = keyid_bits;
}
static void init_intel_energy_perf(struct cpuinfo_x86 *c)
--
2.16.1
