Re: [RFC PATCH 1/3] x86/cpu: Unify CPU family, model, stepping calculation

[Paolo Bonzini <pbonzini@redhat.com>]

On 18/11/2015 19:50, Borislav Petkov wrote:
> On Wed, Nov 18, 2015 at 12:35:24PM +0100, Paolo Bonzini wrote:
>> Yes, exactly.  I'm suggesting that the same applies to x86_vendor().  I
>> also prefer x86_cpuid_* to x86_*_cpuid because, once you add two
>> functions in the same family it's nice that they share a prefix.
> 
> Ok, makes sense:
> 
> ---
> commit 804437270083a1aabf87f65f65b32e2ae23121b6
> Author: Borislav Petkov <bp@suse.de>
> Date:   Sat Nov 14 10:54:22 2015 +0100
> 
>     x86/cpu: Unify CPU family, model, stepping calculation
>     
>     Add generic functions which calc family, model and stepping from the
>     CPUID_1.EAX leaf and stick them into the library we have.
>     
>     Rename those which do call CPUID with the prefix "x86_cpuid" as
>     suggested by Paolo Bonzini.
>     
>     No functionality change.
>     
>     Signed-off-by: Borislav Petkov <bp@suse.de>

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>

Let me know if I should include this patch via the KVM tree.  Do you
want it in 4.4?

Paolo

> 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/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
> index 4ddd780aeac9..c311b51efe15 100644
> --- a/arch/x86/kernel/cpu/common.c
> +++ b/arch/x86/kernel/cpu/common.c
> @@ -582,14 +582,9 @@ 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;
> 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/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);
>