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From: Jan Beulich <jbeulich@suse.com>
To: "xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>
Cc: Kevin Tian <kevin.tian@intel.com>
Subject: [PATCH 4/6] VT-d: qinval indexes are only up to 19 bits wide
Date: Thu, 1 Apr 2021 10:45:14 +0200	[thread overview]
Message-ID: <f205b254-9c1c-45fe-48ed-359a7f8d178f@suse.com> (raw)
In-Reply-To: <157e4a65-6d0b-7ea8-1c23-cd393c8c0d7f@suse.com>

There's no need for 64-bit accesses to these registers (outside of
initial setup and dumping).

Also remove some stray blanks.

Signed-off-by: Jan Beulich <jbeulich@suse.com>

--- a/xen/drivers/passthrough/vtd/qinval.c
+++ b/xen/drivers/passthrough/vtd/qinval.c
@@ -42,14 +42,13 @@ static void print_qi_regs(const struct v
 
 static unsigned int qinval_next_index(struct vtd_iommu *iommu)
 {
-    u64 tail;
+    unsigned int tail = dmar_readl(iommu->reg, DMAR_IQT_REG);
 
-    tail = dmar_readq(iommu->reg, DMAR_IQT_REG);
     tail >>= QINVAL_INDEX_SHIFT;
 
     /* (tail+1 == head) indicates a full queue, wait for HW */
-    while ( ( tail + 1 ) % QINVAL_ENTRY_NR ==
-            ( dmar_readq(iommu->reg, DMAR_IQH_REG) >> QINVAL_INDEX_SHIFT ) )
+    while ( (tail + 1) % QINVAL_ENTRY_NR ==
+            (dmar_readl(iommu->reg, DMAR_IQH_REG) >> QINVAL_INDEX_SHIFT) )
         cpu_relax();
 
     return tail;
@@ -57,12 +56,12 @@ static unsigned int qinval_next_index(st
 
 static void qinval_update_qtail(struct vtd_iommu *iommu, unsigned int index)
 {
-    u64 val;
+    unsigned int val;
 
     /* Need hold register lock when update tail */
     ASSERT( spin_is_locked(&iommu->register_lock) );
     val = (index + 1) % QINVAL_ENTRY_NR;
-    dmar_writeq(iommu->reg, DMAR_IQT_REG, (val << QINVAL_INDEX_SHIFT));
+    dmar_writel(iommu->reg, DMAR_IQT_REG, val << QINVAL_INDEX_SHIFT);
 }
 
 static int __must_check queue_invalidate_context_sync(struct vtd_iommu *iommu,



  parent reply	other threads:[~2021-04-01  8:45 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-01  8:42 [PATCH 0/6] VT-d: assorted cleanup Jan Beulich
2021-04-01  8:44 ` [PATCH 1/6] VT-d: improve save/restore of registers across S3 Jan Beulich
2021-04-01  8:44 ` [PATCH 2/6] VT-d: don't open-code dmar_readl() Jan Beulich
2021-04-01  8:44 ` [PATCH 3/6] VT-d: bring print_qi_regs() in line with print_iommu_regs() Jan Beulich
2021-04-01  8:45 ` Jan Beulich [this message]
2021-04-01  8:45 ` [PATCH 5/6] VT-d: avoid pointless use of 64-bit constants Jan Beulich
2021-04-01  8:45 ` [PATCH 6/6] VT-d: drop unused #define-s Jan Beulich
2021-04-13  2:50 ` [PATCH 0/6] VT-d: assorted cleanup Tian, Kevin

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