[Xen-changelog] [qemu-xen stable-4.10] exec: simplify address_space_get_iotlb_entry

[patchbot@xxxxxxx]

commit ae13e2cfa85858d58a4f1c158bb47a395d983c0c
Author:     Peter Xu <peterx@xxxxxxxxxx>
AuthorDate: Tue Oct 10 11:42:46 2017 +0200
Commit:     Michael Roth <mdroth@xxxxxxxxxxxxxxxxxx>
CommitDate: Mon Dec 4 22:42:34 2017 -0600

    exec: simplify address_space_get_iotlb_entry
    
    This patch let address_space_get_iotlb_entry() to use the newly
    introduced page_mask parameter in flatview_do_translate(). Then we
    will be sure the IOTLB can be aligned to page mask, also we should
    nicely support huge pages now when introducing a764040.
    
    Fixes: a764040 ("exec: abstract address_space_do_translate()")
    Signed-off-by: Peter Xu <peterx@xxxxxxxxxx>
    Signed-off-by: Maxime Coquelin <maxime.coquelin@xxxxxxxxxx>
    Acked-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
    Message-Id: <20171010094247.10173-3-maxime.coquelin@xxxxxxxxxx>
    Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
    (cherry picked from commit 076a93d7972c9c1e3839d2f65edc32568a2cce93)
    Signed-off-by: Michael Roth <mdroth@xxxxxxxxxxxxxxxxxx>
---
 exec.c | 31 ++++++++++---------------------
 1 file changed, 10 insertions(+), 21 deletions(-)

diff --git a/exec.c b/exec.c
index 2fd65dc..9a7600e 100644
--- a/exec.c
+++ b/exec.c
@@ -557,14 +557,14 @@ IOMMUTLBEntry address_space_get_iotlb_entry(AddressSpace 
*as, hwaddr addr,
                                             bool is_write)
 {
     MemoryRegionSection section;
-    hwaddr xlat, plen;
+    hwaddr xlat, page_mask;
 
-    /* Try to get maximum page mask during translation. */
-    plen = (hwaddr)-1;
-
-    /* This can never be MMIO. */
-    section = flatview_do_translate(address_space_to_flatview(as), addr,
-                                    &xlat, &plen, NULL, is_write, false, &as);
+    /*
+     * This can never be MMIO, and we don't really care about plen,
+     * but page mask.
+     */
+    section = flatview_do_translate(address_space_to_flatview(as), addr, &xlat,
+                                    NULL, &page_mask, is_write, false, &as);
 
     /* Illegal translation */
     if (section.mr == &io_mem_unassigned) {
@@ -575,22 +575,11 @@ IOMMUTLBEntry address_space_get_iotlb_entry(AddressSpace 
*as, hwaddr addr,
     xlat += section.offset_within_address_space -
         section.offset_within_region;
 
-    if (plen == (hwaddr)-1) {
-        /*
-         * We use default page size here. Logically it only happens
-         * for identity mappings.
-         */
-        plen = TARGET_PAGE_SIZE;
-    }
-
-    /* Convert to address mask */
-    plen -= 1;
-
     return (IOMMUTLBEntry) {
         .target_as = as,
-        .iova = addr & ~plen,
-        .translated_addr = xlat & ~plen,
-        .addr_mask = plen,
+        .iova = addr & ~page_mask,
+        .translated_addr = xlat & ~page_mask,
+        .addr_mask = page_mask,
         /* IOTLBs are for DMAs, and DMA only allows on RAMs. */
         .perm = IOMMU_RW,
     };
--
generated by git-patchbot for /home/xen/git/qemu-xen.git#stable-4.10

_______________________________________________
Xen-changelog mailing list
Xen-changelog@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/xen-changelog