xen: fix performance decrease with asid assignment
PATCH 1/1 xen: fix performance decrease with asid assignment
Do not clear asid cleanbit unconditionally. This shaves off 100 cycles from the VMRUN instruction.
Signed-off-by Christoph Egger <[email protected]>
Signature · 6 lines
---to satisfy European Law for business letters: Advanced Micro Devices GmbH Einsteinring 24, 85689 Dornach b. Muenchen Geschaeftsfuehrer: Alberto Bozzo, Andrew Bowd Sitz: Dornach, Gemeinde Aschheim, Landkreis Muenchen Registergericht Muenchen, HRB Nr. 43632
xen/arch/x86/hvm/svm/asid.c +2 -1
@@ -63,7 +63,8 @@ void svm_asid_handle_vmrun(void)return ; } -vmcb_set_guest_asid (vmcb, p_asid->asid); +if (vmcb_get_guest_asid (vmcb) != p_asid->asid) +vmcb_set_guest_asid (vmcb, p_asid->asid); vmcb->tlb_control = need_flush; }
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