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* [PATCH] x86: cap address bits CPUID output
@ 2016-05-02 15:11 Jan Beulich
  2016-05-09 10:13 ` Ping: " Jan Beulich
  2016-05-09 12:35 ` Andrew Cooper
  0 siblings, 2 replies; 4+ messages in thread
From: Jan Beulich @ 2016-05-02 15:11 UTC (permalink / raw)
  To: xen-devel; +Cc: Andrew Cooper, Wei Liu

[-- Attachment #1: Type: text/plain, Size: 3733 bytes --]

Don't use more or report more to guests than we are capable of
handling.

At once simplify the code in hvm_cpuid() and mtrr_top_of_ram().

Signed-off-by: Jan Beulich <jbeulich@suse.com>

--- a/xen/arch/x86/cpu/common.c
+++ b/xen/arch/x86/cpu/common.c
@@ -46,6 +46,7 @@ const struct cpu_dev *__read_mostly cpu_
 
 unsigned int paddr_bits __read_mostly = 36;
 unsigned int hap_paddr_bits __read_mostly = 36;
+unsigned int vaddr_bits __read_mostly = VADDR_BITS;
 
 /*
  * Default host IA32_CR_PAT value to cover all memory types.
@@ -240,7 +241,14 @@ static void __init early_cpu_detect(void
 	if ( cpuid_eax(0x80000000) >= 0x80000008 ) {
 		eax = cpuid_eax(0x80000008);
 		paddr_bits = eax & 0xff;
+		if (paddr_bits > PADDR_BITS)
+			paddr_bits = PADDR_BITS;
+		vaddr_bits = (eax >> 8) & 0xff;
+		if (vaddr_bits > VADDR_BITS)
+			vaddr_bits = VADDR_BITS;
 		hap_paddr_bits = ((eax >> 16) & 0xff) ?: paddr_bits;
+		if (hap_paddr_bits > PADDR_BITS)
+			hap_paddr_bits = PADDR_BITS;
 	}
 }
 
--- a/xen/arch/x86/e820.c
+++ b/xen/arch/x86/e820.c
@@ -451,11 +451,11 @@ static uint64_t __init mtrr_top_of_ram(v
          return 0;
 
     /* Find the physical address size for this CPU. */
-    cpuid(0x80000000, &eax, &ebx, &ecx, &edx);
-    if ( eax >= 0x80000008 )
+    if ( cpuid_eax(0x80000000) >= 0x80000008 )
     {
-        cpuid(0x80000008, &eax, &ebx, &ecx, &edx);
-        phys_bits = (uint8_t)eax;
+        phys_bits = (uint8_t)cpuid_eax(0x80000008);
+        if ( phys_bits > PADDR_BITS )
+            phys_bits = PADDR_BITS;
     }
     addr_mask = ((1ull << phys_bits) - 1) & ~((1ull << 12) - 1);
 
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -3504,19 +3504,19 @@ void hvm_cpuid(unsigned int input, unsig
         break;
 
     case 0x80000008:
+        *eax &= 0xff;
         count = d->arch.paging.gfn_bits + PAGE_SHIFT;
-        if ( (*eax & 0xff) > count )
-            *eax = (*eax & ~0xff) | count;
+        if ( *eax > count )
+            *eax = count;
 
         hvm_cpuid(1, NULL, NULL, NULL, &_edx);
         count = _edx & (cpufeat_mask(X86_FEATURE_PAE) |
                         cpufeat_mask(X86_FEATURE_PSE36)) ? 36 : 32;
-        if ( (*eax & 0xff) < count )
-            *eax = (*eax & ~0xff) | count;
+        if ( *eax < count )
+            *eax = count;
 
         hvm_cpuid(0x80000001, NULL, NULL, NULL, &_edx);
-        *eax = (*eax & ~0xffff00) | (_edx & cpufeat_mask(X86_FEATURE_LM)
-                                     ? 0x3000 : 0x2000);
+        *eax |= _edx & cpufeat_mask(X86_FEATURE_LM) ? vaddr_bits << 8 : 0x2000;
 
         *ebx &= hvm_featureset[FEATURESET_e8b];
         break;
--- a/xen/arch/x86/traps.c
+++ b/xen/arch/x86/traps.c
@@ -1146,6 +1146,7 @@ void pv_cpuid(struct cpu_user_regs *regs
         break;
 
     case 0x80000008:
+        a = paddr_bits | (vaddr_bits << 8);
         b &= pv_featureset[FEATURESET_e8b];
         break;
 
--- a/xen/include/asm-x86/processor.h
+++ b/xen/include/asm-x86/processor.h
@@ -216,10 +216,12 @@ extern bool_t opt_cpu_info;
 extern u32 cpuid_ext_features;
 extern u64 trampoline_misc_enable_off;
 
-/* Maximum width of physical addresses supported by the hardware */
+/* Maximum width of physical addresses supported by the hardware. */
 extern unsigned int paddr_bits;
-/* Max physical address width supported within HAP guests */
+/* Max physical address width supported within HAP guests. */
 extern unsigned int hap_paddr_bits;
+/* Maximum width of virtual addresses supported by the hardware. */
+extern unsigned int vaddr_bits;
 
 extern const struct x86_cpu_id *x86_match_cpu(const struct x86_cpu_id table[]);
 




[-- Attachment #2: x86-cap-vaddr-bits.patch --]
[-- Type: text/plain, Size: 3765 bytes --]

x86: cap address bits CPUID output

Don't use more or report more to guests than we are capable of
handling.

At once simplify the code in hvm_cpuid() and mtrr_top_of_ram().

Signed-off-by: Jan Beulich <jbeulich@suse.com>

--- a/xen/arch/x86/cpu/common.c
+++ b/xen/arch/x86/cpu/common.c
@@ -46,6 +46,7 @@ const struct cpu_dev *__read_mostly cpu_
 
 unsigned int paddr_bits __read_mostly = 36;
 unsigned int hap_paddr_bits __read_mostly = 36;
+unsigned int vaddr_bits __read_mostly = VADDR_BITS;
 
 /*
  * Default host IA32_CR_PAT value to cover all memory types.
@@ -240,7 +241,14 @@ static void __init early_cpu_detect(void
 	if ( cpuid_eax(0x80000000) >= 0x80000008 ) {
 		eax = cpuid_eax(0x80000008);
 		paddr_bits = eax & 0xff;
+		if (paddr_bits > PADDR_BITS)
+			paddr_bits = PADDR_BITS;
+		vaddr_bits = (eax >> 8) & 0xff;
+		if (vaddr_bits > VADDR_BITS)
+			vaddr_bits = VADDR_BITS;
 		hap_paddr_bits = ((eax >> 16) & 0xff) ?: paddr_bits;
+		if (hap_paddr_bits > PADDR_BITS)
+			hap_paddr_bits = PADDR_BITS;
 	}
 }
 
--- a/xen/arch/x86/e820.c
+++ b/xen/arch/x86/e820.c
@@ -451,11 +451,11 @@ static uint64_t __init mtrr_top_of_ram(v
          return 0;
 
     /* Find the physical address size for this CPU. */
-    cpuid(0x80000000, &eax, &ebx, &ecx, &edx);
-    if ( eax >= 0x80000008 )
+    if ( cpuid_eax(0x80000000) >= 0x80000008 )
     {
-        cpuid(0x80000008, &eax, &ebx, &ecx, &edx);
-        phys_bits = (uint8_t)eax;
+        phys_bits = (uint8_t)cpuid_eax(0x80000008);
+        if ( phys_bits > PADDR_BITS )
+            phys_bits = PADDR_BITS;
     }
     addr_mask = ((1ull << phys_bits) - 1) & ~((1ull << 12) - 1);
 
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -3504,19 +3504,19 @@ void hvm_cpuid(unsigned int input, unsig
         break;
 
     case 0x80000008:
+        *eax &= 0xff;
         count = d->arch.paging.gfn_bits + PAGE_SHIFT;
-        if ( (*eax & 0xff) > count )
-            *eax = (*eax & ~0xff) | count;
+        if ( *eax > count )
+            *eax = count;
 
         hvm_cpuid(1, NULL, NULL, NULL, &_edx);
         count = _edx & (cpufeat_mask(X86_FEATURE_PAE) |
                         cpufeat_mask(X86_FEATURE_PSE36)) ? 36 : 32;
-        if ( (*eax & 0xff) < count )
-            *eax = (*eax & ~0xff) | count;
+        if ( *eax < count )
+            *eax = count;
 
         hvm_cpuid(0x80000001, NULL, NULL, NULL, &_edx);
-        *eax = (*eax & ~0xffff00) | (_edx & cpufeat_mask(X86_FEATURE_LM)
-                                     ? 0x3000 : 0x2000);
+        *eax |= _edx & cpufeat_mask(X86_FEATURE_LM) ? vaddr_bits << 8 : 0x2000;
 
         *ebx &= hvm_featureset[FEATURESET_e8b];
         break;
--- a/xen/arch/x86/traps.c
+++ b/xen/arch/x86/traps.c
@@ -1146,6 +1146,7 @@ void pv_cpuid(struct cpu_user_regs *regs
         break;
 
     case 0x80000008:
+        a = paddr_bits | (vaddr_bits << 8);
         b &= pv_featureset[FEATURESET_e8b];
         break;
 
--- a/xen/include/asm-x86/processor.h
+++ b/xen/include/asm-x86/processor.h
@@ -216,10 +216,12 @@ extern bool_t opt_cpu_info;
 extern u32 cpuid_ext_features;
 extern u64 trampoline_misc_enable_off;
 
-/* Maximum width of physical addresses supported by the hardware */
+/* Maximum width of physical addresses supported by the hardware. */
 extern unsigned int paddr_bits;
-/* Max physical address width supported within HAP guests */
+/* Max physical address width supported within HAP guests. */
 extern unsigned int hap_paddr_bits;
+/* Maximum width of virtual addresses supported by the hardware. */
+extern unsigned int vaddr_bits;
 
 extern const struct x86_cpu_id *x86_match_cpu(const struct x86_cpu_id table[]);
 

[-- Attachment #3: Type: text/plain, Size: 126 bytes --]

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^ permalink raw reply	[flat|nested] 4+ messages in thread

* Ping: [PATCH] x86: cap address bits CPUID output
  2016-05-02 15:11 [PATCH] x86: cap address bits CPUID output Jan Beulich
@ 2016-05-09 10:13 ` Jan Beulich
  2016-05-09 12:35 ` Andrew Cooper
  1 sibling, 0 replies; 4+ messages in thread
From: Jan Beulich @ 2016-05-09 10:13 UTC (permalink / raw)
  To: Andrew Cooper; +Cc: xen-devel, Wei Liu

>>> On 02.05.16 at 17:11, <JBeulich@suse.com> wrote:
> Don't use more or report more to guests than we are capable of
> handling.
> 
> At once simplify the code in hvm_cpuid() and mtrr_top_of_ram().
> 
> Signed-off-by: Jan Beulich <jbeulich@suse.com>
> 
> --- a/xen/arch/x86/cpu/common.c
> +++ b/xen/arch/x86/cpu/common.c
> @@ -46,6 +46,7 @@ const struct cpu_dev *__read_mostly cpu_
>  
>  unsigned int paddr_bits __read_mostly = 36;
>  unsigned int hap_paddr_bits __read_mostly = 36;
> +unsigned int vaddr_bits __read_mostly = VADDR_BITS;
>  
>  /*
>   * Default host IA32_CR_PAT value to cover all memory types.
> @@ -240,7 +241,14 @@ static void __init early_cpu_detect(void
>  	if ( cpuid_eax(0x80000000) >= 0x80000008 ) {
>  		eax = cpuid_eax(0x80000008);
>  		paddr_bits = eax & 0xff;
> +		if (paddr_bits > PADDR_BITS)
> +			paddr_bits = PADDR_BITS;
> +		vaddr_bits = (eax >> 8) & 0xff;
> +		if (vaddr_bits > VADDR_BITS)
> +			vaddr_bits = VADDR_BITS;
>  		hap_paddr_bits = ((eax >> 16) & 0xff) ?: paddr_bits;
> +		if (hap_paddr_bits > PADDR_BITS)
> +			hap_paddr_bits = PADDR_BITS;
>  	}
>  }
>  
> --- a/xen/arch/x86/e820.c
> +++ b/xen/arch/x86/e820.c
> @@ -451,11 +451,11 @@ static uint64_t __init mtrr_top_of_ram(v
>           return 0;
>  
>      /* Find the physical address size for this CPU. */
> -    cpuid(0x80000000, &eax, &ebx, &ecx, &edx);
> -    if ( eax >= 0x80000008 )
> +    if ( cpuid_eax(0x80000000) >= 0x80000008 )
>      {
> -        cpuid(0x80000008, &eax, &ebx, &ecx, &edx);
> -        phys_bits = (uint8_t)eax;
> +        phys_bits = (uint8_t)cpuid_eax(0x80000008);
> +        if ( phys_bits > PADDR_BITS )
> +            phys_bits = PADDR_BITS;
>      }
>      addr_mask = ((1ull << phys_bits) - 1) & ~((1ull << 12) - 1);
>  
> --- a/xen/arch/x86/hvm/hvm.c
> +++ b/xen/arch/x86/hvm/hvm.c
> @@ -3504,19 +3504,19 @@ void hvm_cpuid(unsigned int input, unsig
>          break;
>  
>      case 0x80000008:
> +        *eax &= 0xff;
>          count = d->arch.paging.gfn_bits + PAGE_SHIFT;
> -        if ( (*eax & 0xff) > count )
> -            *eax = (*eax & ~0xff) | count;
> +        if ( *eax > count )
> +            *eax = count;
>  
>          hvm_cpuid(1, NULL, NULL, NULL, &_edx);
>          count = _edx & (cpufeat_mask(X86_FEATURE_PAE) |
>                          cpufeat_mask(X86_FEATURE_PSE36)) ? 36 : 32;
> -        if ( (*eax & 0xff) < count )
> -            *eax = (*eax & ~0xff) | count;
> +        if ( *eax < count )
> +            *eax = count;
>  
>          hvm_cpuid(0x80000001, NULL, NULL, NULL, &_edx);
> -        *eax = (*eax & ~0xffff00) | (_edx & cpufeat_mask(X86_FEATURE_LM)
> -                                     ? 0x3000 : 0x2000);
> +        *eax |= _edx & cpufeat_mask(X86_FEATURE_LM) ? vaddr_bits << 8 : 
> 0x2000;
>  
>          *ebx &= hvm_featureset[FEATURESET_e8b];
>          break;
> --- a/xen/arch/x86/traps.c
> +++ b/xen/arch/x86/traps.c
> @@ -1146,6 +1146,7 @@ void pv_cpuid(struct cpu_user_regs *regs
>          break;
>  
>      case 0x80000008:
> +        a = paddr_bits | (vaddr_bits << 8);
>          b &= pv_featureset[FEATURESET_e8b];
>          break;
>  
> --- a/xen/include/asm-x86/processor.h
> +++ b/xen/include/asm-x86/processor.h
> @@ -216,10 +216,12 @@ extern bool_t opt_cpu_info;
>  extern u32 cpuid_ext_features;
>  extern u64 trampoline_misc_enable_off;
>  
> -/* Maximum width of physical addresses supported by the hardware */
> +/* Maximum width of physical addresses supported by the hardware. */
>  extern unsigned int paddr_bits;
> -/* Max physical address width supported within HAP guests */
> +/* Max physical address width supported within HAP guests. */
>  extern unsigned int hap_paddr_bits;
> +/* Maximum width of virtual addresses supported by the hardware. */
> +extern unsigned int vaddr_bits;
>  
>  extern const struct x86_cpu_id *x86_match_cpu(const struct x86_cpu_id 
> table[]);
>  




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^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH] x86: cap address bits CPUID output
  2016-05-02 15:11 [PATCH] x86: cap address bits CPUID output Jan Beulich
  2016-05-09 10:13 ` Ping: " Jan Beulich
@ 2016-05-09 12:35 ` Andrew Cooper
  2016-05-09 12:38   ` Jan Beulich
  1 sibling, 1 reply; 4+ messages in thread
From: Andrew Cooper @ 2016-05-09 12:35 UTC (permalink / raw)
  To: Jan Beulich, xen-devel; +Cc: Wei Liu

On 02/05/16 16:11, Jan Beulich wrote:
> --- a/xen/arch/x86/e820.c
> +++ b/xen/arch/x86/e820.c
> @@ -451,11 +451,11 @@ static uint64_t __init mtrr_top_of_ram(v
>           return 0;
>  
>      /* Find the physical address size for this CPU. */
> -    cpuid(0x80000000, &eax, &ebx, &ecx, &edx);
> -    if ( eax >= 0x80000008 )
> +    if ( cpuid_eax(0x80000000) >= 0x80000008 )

You indicated in review of my cpuid series that this check is buggy, and
the upper half needs comparing exactly to 0x8000.

It occurs to me that early_cpu_detect() really should be callled
earlier, to avoid needing to recalculate this information.

~Andrew

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^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH] x86: cap address bits CPUID output
  2016-05-09 12:35 ` Andrew Cooper
@ 2016-05-09 12:38   ` Jan Beulich
  0 siblings, 0 replies; 4+ messages in thread
From: Jan Beulich @ 2016-05-09 12:38 UTC (permalink / raw)
  To: Andrew Cooper; +Cc: xen-devel, Wei Liu

>>> On 09.05.16 at 14:35, <andrew.cooper3@citrix.com> wrote:
> On 02/05/16 16:11, Jan Beulich wrote:
>> --- a/xen/arch/x86/e820.c
>> +++ b/xen/arch/x86/e820.c
>> @@ -451,11 +451,11 @@ static uint64_t __init mtrr_top_of_ram(v
>>           return 0;
>>  
>>      /* Find the physical address size for this CPU. */
>> -    cpuid(0x80000000, &eax, &ebx, &ecx, &edx);
>> -    if ( eax >= 0x80000008 )
>> +    if ( cpuid_eax(0x80000000) >= 0x80000008 )
> 
> You indicated in review of my cpuid series that this check is buggy, and
> the upper half needs comparing exactly to 0x8000.

Oh, indeed. How did I forget?

> It occurs to me that early_cpu_detect() really should be callled
> earlier, to avoid needing to recalculate this information.

Well, I had (briefly) looked at that option, but iirc it didn't
seem feasible to move it up as early as we'd need it to be.

Jan


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^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2016-05-09 12:39 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2016-05-02 15:11 [PATCH] x86: cap address bits CPUID output Jan Beulich
2016-05-09 10:13 ` Ping: " Jan Beulich
2016-05-09 12:35 ` Andrew Cooper
2016-05-09 12:38   ` Jan Beulich

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