[Xen-devel] [PATCH] xen/x86/pvh: Use HVM's flush_tlb_others op

[Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>]

Using MMUEXT_TLB_FLUSH_MULTI doesn't buy us much since the hypervisor
will likely perform same IPIs as would have the guest.

More importantly, using MMUEXT_INVLPG_MULTI may not to invalidate the
guest's address on remote CPU (when, for example, VCPU from another guest
is running there).

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
Suggested-by: Jan Beulich <jbeulich@xxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx # 3.14+
---
 arch/x86/xen/mmu.c |    9 ++-------
 1 files changed, 2 insertions(+), 7 deletions(-)

diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index 9c479fe..9ed7eed 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -2495,14 +2495,9 @@ void __init xen_init_mmu_ops(void)
 {
        x86_init.paging.pagetable_init = xen_pagetable_init;
 
-       /* Optimization - we can use the HVM one but it has no idea which
-        * VCPUs are descheduled - which means that it will needlessly IPI
-        * them. Xen knows so let it do the job.
-        */
-       if (xen_feature(XENFEAT_auto_translated_physmap)) {
-               pv_mmu_ops.flush_tlb_others = xen_flush_tlb_others;
+       if (xen_feature(XENFEAT_auto_translated_physmap))
                return;
-       }
+
        pv_mmu_ops = xen_mmu_ops;
 
        memset(dummy_mapping, 0xff, PAGE_SIZE);
-- 
1.7.1


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