[Xen-devel] [PATCH] x86/cpuid: Fix booting on AMD Phenom 6-core platform

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

c/s 5cecf60f4 "x86/cpuid: Handle leaf 0x1 in guest_cpuid()" causes Linux 4.10
to crash during boot.

It turns out to be because of the reported apic_id, which was altered to be
more consistent across guests.  Revert back to the previous behaviour, by
limiting the apic_id adjustment to HVM guests only.  Whomever gets to fixes
topology representation is going to have a lot of fun with non-power-of-2 AMD
boxes.

Reported-by: Sander Eikelenboom <linux@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
CC: Jan Beulich <JBeulich@xxxxxxxx>
---
 xen/arch/x86/cpuid.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/xen/arch/x86/cpuid.c b/xen/arch/x86/cpuid.c
index 0dd35dc..d6f6b88 100644
--- a/xen/arch/x86/cpuid.c
+++ b/xen/arch/x86/cpuid.c
@@ -749,7 +749,8 @@ void guest_cpuid(const struct vcpu *v, uint32_t leaf,
     case 0x1:
         /* TODO: Rework topology logic. */
         res->b &= 0x00ffffffu;
-        res->b |= (v->vcpu_id * 2) << 24;
+        if ( has_hvm_container_domain(d) )
+            res->b |= (v->vcpu_id * 2) << 24;
 
         /* TODO: Rework vPMU control in terms of toolstack choices. */
         if ( vpmu_available(v) &&
-- 
2.1.4


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