2020-09-11 19:36:52

by Krish Sadhukhan

Subject: [PATCH 1/4 v3] x86: AMD: Replace numeric value for SME CPUID leaf with a #define

Signed-off-by: Krish Sadhukhan <[email protected]>
---
arch/x86/boot/compressed/mem_encrypt.S | 5 +++--
arch/x86/include/asm/cpufeatures.h | 5 +++++
arch/x86/kernel/cpu/amd.c | 2 +-
arch/x86/kernel/cpu/scattered.c | 4 ++--
arch/x86/kvm/cpuid.c | 2 +-
arch/x86/kvm/svm/svm.c | 4 ++--
arch/x86/mm/mem_encrypt_identity.c | 4 ++--
7 files changed, 16 insertions(+), 10 deletions(-)

diff --git a/arch/x86/boot/compressed/mem_encrypt.S b/arch/x86/boot/compressed/mem_encrypt.S
index dd07e7b41b11..22e30b0c0d19 100644
--- a/arch/x86/boot/compressed/mem_encrypt.S
+++ b/arch/x86/boot/compressed/mem_encrypt.S
@@ -12,6 +12,7 @@
#include <asm/processor-flags.h>
#include <asm/msr.h>
#include <asm/asm-offsets.h>
+#include <asm/cpufeatures.h>

.text
.code32
@@ -31,7 +32,7 @@ SYM_FUNC_START(get_sev_encryption_bit)

movl $0x80000000, %eax /* CPUID to check the highest leaf */
cpuid
- cmpl $0x8000001f, %eax /* See if 0x8000001f is available */
+ cmpl $CPUID_AMD_SME, %eax /* See if 0x8000001f is available */
jb .Lno_sev

/*
@@ -40,7 +41,7 @@ SYM_FUNC_START(get_sev_encryption_bit)
* CPUID Fn8000_001F[EBX] - Bits 5:0
* Pagetable bit position used to indicate encryption
*/
- movl $0x8000001f, %eax
+ movl $CPUID_AMD_SME, %eax
cpuid
bt $1, %eax /* Check if SEV is available */
jnc .Lno_sev
diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index 2901d5df4366..81335e6fe47d 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -10,6 +10,11 @@
#include <asm/disabled-features.h>
#endif

+/*
+ * AMD CPUID functions
+ */
+#define CPUID_AMD_SME 0x8000001f /* Secure Memory Encryption */
+
/*
* Defines x86 CPU feature bits
*/
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index dcc3d943c68f..4507ededb978 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -630,7 +630,7 @@ 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 -= (cpuid_ebx(CPUID_AMD_SME) >> 6) & 0x3f;

if (IS_ENABLED(CONFIG_X86_32))
goto clear_all;
diff --git a/arch/x86/kernel/cpu/scattered.c b/arch/x86/kernel/cpu/scattered.c
index 62b137c3c97a..033c112e03fc 100644
--- a/arch/x86/kernel/cpu/scattered.c
+++ b/arch/x86/kernel/cpu/scattered.c
@@ -39,8 +39,8 @@ static const struct cpuid_bit cpuid_bits[] = {
{ X86_FEATURE_CPB, CPUID_EDX, 9, 0x80000007, 0 },
{ X86_FEATURE_PROC_FEEDBACK, CPUID_EDX, 11, 0x80000007, 0 },
{ X86_FEATURE_MBA, CPUID_EBX, 6, 0x80000008, 0 },
- { X86_FEATURE_SME, CPUID_EAX, 0, 0x8000001f, 0 },
- { X86_FEATURE_SEV, CPUID_EAX, 1, 0x8000001f, 0 },
+ { X86_FEATURE_SME, CPUID_EAX, 0, CPUID_AMD_SME, 0 },
+ { X86_FEATURE_SEV, CPUID_EAX, 1, CPUID_AMD_SME, 0 },
{ 0, 0, 0, 0, 0 }
};

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 3fd6eec202d7..95863e767d3d 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -756,7 +756,7 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
entry->edx = 0;
break;
case 0x80000000:
- entry->eax = min(entry->eax, 0x8000001f);
+ entry->eax = min(entry->eax, CPUID_AMD_SME);
break;
case 0x80000001:
cpuid_entry_override(entry, CPUID_8000_0001_EDX);
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 0194336b64a4..a4e92ae399b4 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -749,7 +749,7 @@ static __init void svm_adjust_mmio_mask(void)
u64 msr, mask;

/* If there is no memory encryption support, use existing mask */
- if (cpuid_eax(0x80000000) < 0x8000001f)
+ if (cpuid_eax(0x80000000) < CPUID_AMD_SME)
return;

/* If memory encryption is not enabled, use existing mask */
@@ -757,7 +757,7 @@ static __init void svm_adjust_mmio_mask(void)
if (!(msr & MSR_K8_SYSCFG_MEM_ENCRYPT))
return;

- enc_bit = cpuid_ebx(0x8000001f) & 0x3f;
+ enc_bit = cpuid_ebx(CPUID_AMD_SME) & 0x3f;
mask_bit = boot_cpu_data.x86_phys_bits;

/* Increment the mask bit if it is the same as the encryption bit */
diff --git a/arch/x86/mm/mem_encrypt_identity.c b/arch/x86/mm/mem_encrypt_identity.c
index e2b0e2ac07bb..cbe600dd357b 100644
--- a/arch/x86/mm/mem_encrypt_identity.c
+++ b/arch/x86/mm/mem_encrypt_identity.c
@@ -498,7 +498,7 @@ void __init sme_enable(struct boot_params *bp)
eax = 0x80000000;
ecx = 0;
native_cpuid(&eax, &ebx, &ecx, &edx);
- if (eax < 0x8000001f)
+ if (eax < CPUID_AMD_SME)
return;

#define AMD_SME_BIT BIT(0)
@@ -520,7 +520,7 @@ void __init sme_enable(struct boot_params *bp)
* CPUID Fn8000_001F[EBX]
* - Bits 5:0 - Pagetable bit position used to indicate encryption
*/
- eax = 0x8000001f;
+ eax = CPUID_AMD_SME;
ecx = 0;
native_cpuid(&eax, &ebx, &ecx, &edx);
if (!(eax & feature_mask))
--
2.18.4

2020-09-11 21:23:22

by Borislav Petkov

Subject: Re: [PATCH 1/4 v3] x86: AMD: Replace numeric value for SME CPUID leaf with a #define

On Fri, Sep 11, 2020 at 07:25:58PM +0000, Krish Sadhukhan wrote:

<-- patches need commit message.

...

> diff --git a/arch/x86/kernel/cpu/scattered.c b/arch/x86/kernel/cpu/scattered.c
> index 62b137c3c97a..033c112e03fc 100644
> --- a/arch/x86/kernel/cpu/scattered.c
> +++ b/arch/x86/kernel/cpu/scattered.c
> @@ -39,8 +39,8 @@ static const struct cpuid_bit cpuid_bits[] = {
> { X86_FEATURE_CPB, CPUID_EDX, 9, 0x80000007, 0 },
> { X86_FEATURE_PROC_FEEDBACK, CPUID_EDX, 11, 0x80000007, 0 },
> { X86_FEATURE_MBA, CPUID_EBX, 6, 0x80000008, 0 },
> - { X86_FEATURE_SME, CPUID_EAX, 0, 0x8000001f, 0 },
> - { X86_FEATURE_SEV, CPUID_EAX, 1, 0x8000001f, 0 },
> + { X86_FEATURE_SME, CPUID_EAX, 0, CPUID_AMD_SME, 0 },
> + { X86_FEATURE_SEV, CPUID_EAX, 1, CPUID_AMD_SME, 0 },

So this one gets a name and all the others above don't?

This fact should've given you a hint that there's no need for naming
CPUID leafs - it is easier to grep CPU manuals by the values so you can
drop this patch.

Thx.

--
Regards/Gruss,
Boris.

https://people.kernel.org/tglx/notes-about-netiquette

2020-09-12 06:55:45

by Paolo Bonzini

Subject: Re: [PATCH 1/4 v3] x86: AMD: Replace numeric value for SME CPUID leaf with a #define

On 11/09/20 23:21, Borislav Petkov wrote:
> On Fri, Sep 11, 2020 at 07:25:58PM +0000, Krish Sadhukhan wrote:
>
> <-- patches need commit message.
>
> ...
>
>> diff --git a/arch/x86/kernel/cpu/scattered.c b/arch/x86/kernel/cpu/scattered.c
>> index 62b137c3c97a..033c112e03fc 100644
>> --- a/arch/x86/kernel/cpu/scattered.c
>> +++ b/arch/x86/kernel/cpu/scattered.c
>> @@ -39,8 +39,8 @@ static const struct cpuid_bit cpuid_bits[] = {
>> { X86_FEATURE_CPB, CPUID_EDX, 9, 0x80000007, 0 },
>> { X86_FEATURE_PROC_FEEDBACK, CPUID_EDX, 11, 0x80000007, 0 },
>> { X86_FEATURE_MBA, CPUID_EBX, 6, 0x80000008, 0 },
>> - { X86_FEATURE_SME, CPUID_EAX, 0, 0x8000001f, 0 },
>> - { X86_FEATURE_SEV, CPUID_EAX, 1, 0x8000001f, 0 },
>> + { X86_FEATURE_SME, CPUID_EAX, 0, CPUID_AMD_SME, 0 },
>> + { X86_FEATURE_SEV, CPUID_EAX, 1, CPUID_AMD_SME, 0 },
>
> So this one gets a name and all the others above don't?
>
> This fact should've given you a hint that there's no need for naming
> CPUID leafs - it is easier to grep CPU manuals by the values so you can
> drop this patch.

Also, there'd be confusion between the CPUID_* enum in
arch/x86/include/asm/cpufeature.h.

Paolo