We've already scanned features by the time init_e820() is called. Remove the
cpuid() calls.
Signed-off-by: Andrew Cooper <andrew.coop...@citrix.com>
---
CC: Jan Beulich <jbeul...@suse.com>
CC: Roger Pau Monné <roger....@citrix.com>
Backporting. Not sure it's worth backporing, but it is safe (just) to
backport past commit 365f408339d3 ("x86/boot: Load microcode much earlier on
boot"). That commit was the last one to reposition early_cpu_init().
I'm pretty sure that all 64bit CPUs have MTRR, but I'm less certain if
dropping the check is wise given the variety of VM configurations that exist.
---
xen/arch/x86/e820.c | 14 ++------------
1 file changed, 2 insertions(+), 12 deletions(-)
diff --git a/xen/arch/x86/e820.c b/xen/arch/x86/e820.c
index e052e84de75c..ca577c0bde0f 100644
--- a/xen/arch/x86/e820.c
+++ b/xen/arch/x86/e820.c
@@ -421,21 +421,12 @@ static void __init clip_to_limit(uint64_t limit, const
char *warnmsg)
/* Conservative estimate of top-of-RAM by looking for MTRR WB regions. */
static uint64_t __init mtrr_top_of_ram(void)
{
- uint32_t eax, ebx, ecx, edx;
uint64_t mtrr_cap, mtrr_def, addr_mask, base, mask, top;
unsigned int i;
/* By default we check only Intel systems. */
if ( e820_mtrr_clip == -1 )
- {
- char vendor[13];
- cpuid(0x00000000, &eax,
- (uint32_t *)&vendor[0],
- (uint32_t *)&vendor[8],
- (uint32_t *)&vendor[4]);
- vendor[12] = '\0';
- e820_mtrr_clip = !strcmp(vendor, "GenuineIntel");
- }
+ e820_mtrr_clip = boot_cpu_data.x86_vendor == X86_VENDOR_INTEL;
if ( !e820_mtrr_clip )
return 0;
@@ -444,8 +435,7 @@ static uint64_t __init mtrr_top_of_ram(void)
printk("Checking MTRR ranges...\n");
/* Does the CPU support architectural MTRRs? */
- cpuid(0x00000001, &eax, &ebx, &ecx, &edx);
- if ( !test_bit(X86_FEATURE_MTRR & 31, &edx) )
+ if ( !cpu_has_mtrr )
return 0;
/* paddr_bits must have been set at this point */
--
2.39.5
