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From: Roger Pau Monne <roger.pau@citrix.com>
To: <xen-devel@lists.xenproject.org>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>, Wei Liu <wl@xen.org>,
	George Dunlap <george.dunlap@citrix.com>,
	Jan Beulich <jbeulich@suse.com>,
	Roger Pau Monne <roger.pau@citrix.com>
Subject: [PATCH] x86/hap: be more selective with assisted TLB flush
Date: Wed, 29 Apr 2020 19:36:01 +0200	[thread overview]
Message-ID: <20200429173601.77605-1-roger.pau@citrix.com> (raw)

When doing an assisted flush on HAP the purpose of the
on_selected_cpus is just to trigger a vmexit on remote CPUs that are
in guest context, and hence just using is_vcpu_dirty_cpu is too lax,
also check that the vCPU is running.

While there also pass NULL as the data parameter of on_selected_cpus,
the dummy handler doesn't consume the data in any way.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
---
 xen/arch/x86/mm/hap/hap.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/xen/arch/x86/mm/hap/hap.c b/xen/arch/x86/mm/hap/hap.c
index 580d1c2164..0275cdf5c8 100644
--- a/xen/arch/x86/mm/hap/hap.c
+++ b/xen/arch/x86/mm/hap/hap.c
@@ -719,7 +719,7 @@ static bool flush_tlb(bool (*flush_vcpu)(void *ctxt, struct vcpu *v),
         hvm_asid_flush_vcpu(v);
 
         cpu = read_atomic(&v->dirty_cpu);
-        if ( cpu != this_cpu && is_vcpu_dirty_cpu(cpu) )
+        if ( cpu != this_cpu && is_vcpu_dirty_cpu(cpu) && v->is_running )
             __cpumask_set_cpu(cpu, mask);
     }
 
@@ -729,7 +729,7 @@ static bool flush_tlb(bool (*flush_vcpu)(void *ctxt, struct vcpu *v),
      * not currently running will already be flushed when scheduled because of
      * the ASID tickle done in the loop above.
      */
-    on_selected_cpus(mask, dummy_flush, mask, 0);
+    on_selected_cpus(mask, dummy_flush, NULL, 0);
 
     return true;
 }
-- 
2.26.0



             reply	other threads:[~2020-04-29 17:36 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-29 17:36 Roger Pau Monne [this message]
2020-04-30  7:20 ` [PATCH] x86/hap: be more selective with assisted TLB flush Jan Beulich
2020-04-30  8:28   ` Roger Pau Monné
2020-04-30  8:33     ` Jan Beulich
2020-04-30 16:19       ` Andrew Cooper
2020-04-30 18:09         ` Roger Pau Monné

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