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From: CLEMENT MATHIEU--DRIF <clement.mathieu--drif@eviden.com>
To: "qemu-devel@nongnu.org" <qemu-devel@nongnu.org>
Cc: "jasowang@redhat.com" <jasowang@redhat.com>,
	"zhenzhong.duan@intel.com" <zhenzhong.duan@intel.com>,
	"kevin.tian@intel.com" <kevin.tian@intel.com>,
	"yi.l.liu@intel.com" <yi.l.liu@intel.com>,
	"peterx@redhat.com" <peterx@redhat.com>,
	"mst@redhat.com" <mst@redhat.com>,
	CLEMENT MATHIEU--DRIF <clement.mathieu--drif@eviden.com>
Subject: [PATCH v4 2/3] intel_iommu: Use BQL_LOCK_GUARD to manage cleanup automatically
Date: Mon, 28 Apr 2025 05:12:54 +0000	[thread overview]
Message-ID: <20250428051235.10767-3-clement.mathieu--drif@eviden.com> (raw)
In-Reply-To: <20250428051235.10767-1-clement.mathieu--drif@eviden.com>

vtd_switch_address_space needs to take the BQL if not already held.
Use BQL_LOCK_GUARD to make the iommu implementation more consistent.

Signed-off-by: Clement Mathieu--Drif <clement.mathieu--drif@eviden.com>
---
 hw/i386/intel_iommu.c | 10 +---------
 1 file changed, 1 insertion(+), 9 deletions(-)

diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
index cc8c9857e1..b7855f4b87 100644
--- a/hw/i386/intel_iommu.c
+++ b/hw/i386/intel_iommu.c
@@ -1728,8 +1728,6 @@ static bool vtd_as_pt_enabled(VTDAddressSpace *as)
 static bool vtd_switch_address_space(VTDAddressSpace *as)
 {
     bool use_iommu, pt;
-    /* Whether we need to take the BQL on our own */
-    bool take_bql = !bql_locked();
 
     assert(as);
 
@@ -1746,9 +1744,7 @@ static bool vtd_switch_address_space(VTDAddressSpace *as)
      * from vtd_pt_enable_fast_path(). However the memory APIs need
      * it. We'd better make sure we have had it already, or, take it.
      */
-    if (take_bql) {
-        bql_lock();
-    }
+    BQL_LOCK_GUARD();
 
     /* Turn off first then on the other */
     if (use_iommu) {
@@ -1801,10 +1797,6 @@ static bool vtd_switch_address_space(VTDAddressSpace *as)
         memory_region_set_enabled(&as->iommu_ir_fault, false);
     }
 
-    if (take_bql) {
-        bql_unlock();
-    }
-
     return use_iommu;
 }
 
-- 
2.49.0


  parent reply	other threads:[~2025-04-28  5:14 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-04-28  5:12 [PATCH v4 0/3] intel_iommu: Fix locking issues CLEMENT MATHIEU--DRIF
2025-04-28  5:12 ` [PATCH v4 1/3] intel_iommu: Take the bql before registering a new address space CLEMENT MATHIEU--DRIF
2025-04-28  5:12 ` CLEMENT MATHIEU--DRIF [this message]
2025-04-28  5:12 ` [PATCH v4 3/3] intel_iommu: Take the VTD lock when looking for and creating address spaces CLEMENT MATHIEU--DRIF
2025-04-28  8:55   ` Duan, Zhenzhong
2025-04-28 14:32     ` CLEMENT MATHIEU--DRIF
2025-04-29  6:01       ` Duan, Zhenzhong
2025-04-30 12:58         ` CLEMENT MATHIEU--DRIF

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