[Xen-devel] [PATCH 2/3] x86/boot: Cache cpu_has_hypervisor very early on boot

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

We cache Long Mode and No Execute early on boot, so take the opportunity to
cache HYPERVISOR early as well.

Replace opencoded early access to the feature bit.

Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
CC: Jan Beulich <JBeulich@xxxxxxxx>
CC: Wei Liu <wl@xxxxxxx>
CC: Roger Pau Monné <roger.pau@xxxxxxxxxx>
CC: Sergey Dyasli <sergey.dyasli@xxxxxxxxxx>
CC: Juergen Gross <jgross@xxxxxxxx>
---
 xen/arch/x86/apic.c         | 2 +-
 xen/arch/x86/boot/head.S    | 4 ++++
 xen/arch/x86/efi/efi-boot.h | 6 ++++--
 xen/arch/x86/guest/xen.c    | 6 +-----
 xen/arch/x86/mm.c           | 3 +--
 5 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/xen/arch/x86/apic.c b/xen/arch/x86/apic.c
index a5f7b05d5a..a8ee18636f 100644
--- a/xen/arch/x86/apic.c
+++ b/xen/arch/x86/apic.c
@@ -1156,7 +1156,7 @@ static void __init check_deadline_errata(void)
     const struct x86_cpu_id *m;
     unsigned int rev;
 
-    if ( boot_cpu_has(X86_FEATURE_HYPERVISOR) )
+    if ( cpu_has_hypervisor )
         return;
 
     m = x86_match_cpu(deadline_match);
diff --git a/xen/arch/x86/boot/head.S b/xen/arch/x86/boot/head.S
index 77309e3c82..8d0ffbd1b0 100644
--- a/xen/arch/x86/boot/head.S
+++ b/xen/arch/x86/boot/head.S
@@ -630,6 +630,10 @@ trampoline_setup:
 
 1:
         /* Interrogate CPU extended features via CPUID. */
+        mov     $1, %eax
+        cpuid
+        mov     %ecx, sym_fs(boot_cpu_data) + 
CPUINFO_FEATURE_OFFSET(X86_FEATURE_HYPERVISOR)
+
         mov     $0x80000000,%eax
         cpuid
         shld    $16,%eax,%ecx
diff --git a/xen/arch/x86/efi/efi-boot.h b/xen/arch/x86/efi/efi-boot.h
index cde193a771..232972eedf 100644
--- a/xen/arch/x86/efi/efi-boot.h
+++ b/xen/arch/x86/efi/efi-boot.h
@@ -637,11 +637,13 @@ static void __init efi_arch_handle_module(struct file 
*file, const CHAR16 *name,
 static void __init efi_arch_cpu(void)
 {
     uint32_t eax = cpuid_eax(0x80000000);
+    uint32_t *caps = boot_cpu_data.x86_capability;
+
+    caps[cpufeat_word(X86_FEATURE_HYPERVISOR)] = cpuid_ecx(1);
 
     if ( (eax >> 16) == 0x8000 && eax > 0x80000000 )
     {
-        boot_cpu_data.x86_capability[cpufeat_word(X86_FEATURE_SYSCALL)]
-            = cpuid_edx(0x80000001);
+        caps[cpufeat_word(X86_FEATURE_SYSCALL)] = cpuid_edx(0x80000001);
 
         if ( cpu_has_nx )
             trampoline_efer |= EFER_NX;
diff --git a/xen/arch/x86/guest/xen.c b/xen/arch/x86/guest/xen.c
index 7b7a5badab..a329e7c886 100644
--- a/xen/arch/x86/guest/xen.c
+++ b/xen/arch/x86/guest/xen.c
@@ -69,11 +69,7 @@ static void __init find_xen_leaves(void)
 
 void __init probe_hypervisor(void)
 {
-    if ( xen_guest )
-        return;
-
-    /* Too early to use cpu_has_hypervisor */
-    if ( !(cpuid_ecx(1) & cpufeat_mask(X86_FEATURE_HYPERVISOR)) )
+    if ( xen_guest || !cpu_has_hypervisor )
         return;
 
     find_xen_leaves();
diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index 57f22775ac..bd8182f40f 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -6112,8 +6112,7 @@ const struct platform_bad_page *__init 
get_platform_badpages(unsigned int *array
     case 0x000506e0: /* errata SKL167 / SKW159 */
     case 0x000806e0: /* erratum KBL??? */
     case 0x000906e0: /* errata KBL??? / KBW114 / CFW103 */
-        *array_size = (cpuid_eax(0) >= 7 &&
-                       !(cpuid_ecx(1) & cpufeat_mask(X86_FEATURE_HYPERVISOR)) 
&&
+        *array_size = (cpuid_eax(0) >= 7 && !cpu_has_hypervisor &&
                        (cpuid_count_ebx(7, 0) & 
cpufeat_mask(X86_FEATURE_HLE)));
         return &hle_bad_page;
     }
-- 
2.11.0


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel