[xen master] VT-d: qinval indexes are only up to 19 bits wide

[patchbot@xxxxxxx]

commit 1b5d913fa0b3e4b9a8bba10c1db83082193bcc7a
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Tue Apr 13 10:16:06 2021 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Tue Apr 13 10:16:06 2021 +0200

    VT-d: qinval indexes are only up to 19 bits wide
    
    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@xxxxxxxx>
    Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx>
---
 xen/drivers/passthrough/vtd/qinval.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/xen/drivers/passthrough/vtd/qinval.c 
b/xen/drivers/passthrough/vtd/qinval.c
index 6100e778f3..c0ea19d4bd 100644
--- 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 vtd_iommu *iommu)
 
 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(struct vtd_iommu 
*iommu)
 
 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,
--
generated by git-patchbot for /home/xen/git/xen.git#master