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[18/27] x86/pv: Use per-domain policy information in pv_cpuid()

Message ID 1483533584-8015-19-git-send-email-andrew.cooper3@citrix.com (mailing list archive)
State New, archived
Headers show

Commit Message

Andrew Cooper Jan. 4, 2017, 12:39 p.m. UTC 
... rather than performing runtime adjustments.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
CC: Jan Beulich <JBeulich@suse.com>
---
 xen/arch/x86/traps.c | 44 ++++++++++++--------------------------------
 1 file changed, 12 insertions(+), 32 deletions(-)

Comments

Jan Beulich Jan. 5, 2017, 12:44 p.m. UTC | #1 
>>> On 04.01.17 at 13:39, <andrew.cooper3@citrix.com> wrote:
> --- a/xen/arch/x86/traps.c
> +++ b/xen/arch/x86/traps.c
> @@ -1065,11 +1065,8 @@ void pv_cpuid(struct cpu_user_regs *regs)
>          uint32_t tmp;
>  
>      case 0x00000001:
> -        c &= pv_featureset[FEATURESET_1c];
> -        d &= pv_featureset[FEATURESET_1d];
> -
> -        if ( is_pv_32bit_domain(currd) )
> -            c &= ~cpufeat_mask(X86_FEATURE_CX16);
> +        c = p->basic._1c;
> +        d = p->basic._1d;

Being able to drop the clearing of CX16 is because it depends on
LM, and LM gets cleared explicitly in recalculate_cpuid_policy(). If
that's right (and intended that way),
Reviewed-by: Jan Beulich <jbeulich@suse.com>

Jan
Andrew Cooper Jan. 5, 2017, 12:46 p.m. UTC | #2 
On 05/01/17 12:44, Jan Beulich wrote:
>>>> On 04.01.17 at 13:39, <andrew.cooper3@citrix.com> wrote:
>> --- a/xen/arch/x86/traps.c
>> +++ b/xen/arch/x86/traps.c
>> @@ -1065,11 +1065,8 @@ void pv_cpuid(struct cpu_user_regs *regs)
>>          uint32_t tmp;
>>  
>>      case 0x00000001:
>> -        c &= pv_featureset[FEATURESET_1c];
>> -        d &= pv_featureset[FEATURESET_1d];
>> -
>> -        if ( is_pv_32bit_domain(currd) )
>> -            c &= ~cpufeat_mask(X86_FEATURE_CX16);
>> +        c = p->basic._1c;
>> +        d = p->basic._1d;
> Being able to drop the clearing of CX16 is because it depends on
> LM, and LM gets cleared explicitly in recalculate_cpuid_policy(). If
> that's right (and intended that way),
> Reviewed-by: Jan Beulich <jbeulich@suse.com>

Yes.  I will update the commit message to explicitly state that
recalculate_cpuid_policy() performs these adjustments when the policy is
loaded.

~Andrew
diff mbox

Patch

diff --git a/xen/arch/x86/traps.c b/xen/arch/x86/traps.c
index f19e015..1c384cf 100644
--- a/xen/arch/x86/traps.c
+++ b/xen/arch/x86/traps.c
@@ -1065,11 +1065,8 @@  void pv_cpuid(struct cpu_user_regs *regs)
         uint32_t tmp;
 
     case 0x00000001:
-        c &= pv_featureset[FEATURESET_1c];
-        d &= pv_featureset[FEATURESET_1d];
-
-        if ( is_pv_32bit_domain(currd) )
-            c &= ~cpufeat_mask(X86_FEATURE_CX16);
+        c = p->basic._1c;
+        d = p->basic._1d;
 
         if ( !is_pvh_domain(currd) )
         {
@@ -1128,7 +1125,7 @@  void pv_cpuid(struct cpu_user_regs *regs)
              *    Emulated vs Faulted CPUID is distinguised based on whether a
              *    #UD or #GP is currently being serviced.
              */
-            /* OSXSAVE cleared by pv_featureset.  Fast-forward CR4 back in. */
+            /* OSXSAVE clear in policy.  Fast-forward CR4 back in. */
             if ( (curr->arch.pv_vcpu.ctrlreg[4] & X86_CR4_OSXSAVE) ||
                  (regs->entry_vector == TRAP_invalid_op &&
                   guest_kernel_mode(curr, regs) &&
@@ -1204,21 +1201,14 @@  void pv_cpuid(struct cpu_user_regs *regs)
             if ( cpu_has(&current_cpu_data, X86_FEATURE_DSCPL) )
                 c |= cpufeat_mask(X86_FEATURE_DSCPL);
         }
-
-        c |= cpufeat_mask(X86_FEATURE_HYPERVISOR);
         break;
 
     case 0x00000007:
         if ( subleaf == 0 )
         {
-            /* Fold host's FDP_EXCP_ONLY and NO_FPU_SEL into guest's view. */
-            b &= (pv_featureset[FEATURESET_7b0] &
-                  ~special_features[FEATURESET_7b0]);
-            b |= (host_featureset[FEATURESET_7b0] &
-                  special_features[FEATURESET_7b0]);
-
-            c &= pv_featureset[FEATURESET_7c0];
-            d &= pv_featureset[FEATURESET_7d0];
+            b = currd->arch.cpuid->feat._7b0;
+            c = currd->arch.cpuid->feat._7c0;
+            d = currd->arch.cpuid->feat._7d0;
 
             if ( !is_pvh_domain(currd) )
             {
@@ -1227,7 +1217,7 @@  void pv_cpuid(struct cpu_user_regs *regs)
                  * and HVM guests no longer enter a PV codepath.
                  */
 
-                /* OSPKE cleared by pv_featureset.  Fast-forward CR4 back in. */
+                /* OSPKE clear in policy.  Fast-forward CR4 back in. */
                 if ( curr->arch.pv_vcpu.ctrlreg[4] & X86_CR4_PKE )
                     c |= cpufeat_mask(X86_FEATURE_OSPKE);
             }
@@ -1292,15 +1282,15 @@  void pv_cpuid(struct cpu_user_regs *regs)
         }
 
         case 1:
-            a &= pv_featureset[FEATURESET_Da1];
+            a = p->xstate.Da1;
             b = c = d = 0;
             break;
         }
         break;
 
     case 0x80000001:
-        c &= pv_featureset[FEATURESET_e1c];
-        d &= pv_featureset[FEATURESET_e1d];
+        c = p->extd.e1c;
+        d = p->extd.e1d;
 
         /* If not emulating AMD, clear the duplicated features in e1d. */
         if ( currd->arch.x86_vendor != X86_VENDOR_AMD )
@@ -1318,25 +1308,15 @@  void pv_cpuid(struct cpu_user_regs *regs)
         if ( is_hardware_domain(currd) && guest_kernel_mode(curr, regs) &&
              cpu_has_mtrr )
             d |= cpufeat_mask(X86_FEATURE_MTRR);
-
-        if ( is_pv_32bit_domain(currd) )
-        {
-            d &= ~cpufeat_mask(X86_FEATURE_LM);
-            c &= ~cpufeat_mask(X86_FEATURE_LAHF_LM);
-
-            if ( boot_cpu_data.x86_vendor != X86_VENDOR_AMD )
-                d &= ~cpufeat_mask(X86_FEATURE_SYSCALL);
-        }
         break;
 
     case 0x80000007:
-        d &= (pv_featureset[FEATURESET_e7d] |
-              (host_featureset[FEATURESET_e7d] & cpufeat_mask(X86_FEATURE_ITSC)));
+        d = p->extd.e7d;
         break;
 
     case 0x80000008:
         a = paddr_bits | (vaddr_bits << 8);
-        b &= pv_featureset[FEATURESET_e8b];
+        b = p->extd.e8b;
         break;
 
     case 0x00000005: /* MONITOR/MWAIT */