[Xen-changelog] [xen master] x86/HVM: latch linear->phys translation results

[patchbot@xxxxxxx]

commit 67fc274bbec51a99c762aa1fb6c3de661032aa8d
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Tue Jun 14 15:09:51 2016 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Tue Jun 14 15:09:51 2016 +0200

    x86/HVM: latch linear->phys translation results
    
    ... to avoid re-doing the same translation later again (in a retry, for
    example). This doesn't help very often according to my testing, but
    it's pretty cheap to have, and will be of further use subsequently.
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Reviewed-by: Paul Durrant <paul.durrant@xxxxxxxxxx>
    Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
 xen/arch/x86/hvm/emulate.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/xen/arch/x86/hvm/emulate.c b/xen/arch/x86/hvm/emulate.c
index b9cac8e..8a033a3 100644
--- a/xen/arch/x86/hvm/emulate.c
+++ b/xen/arch/x86/hvm/emulate.c
@@ -678,6 +678,19 @@ static struct hvm_mmio_cache *hvmemul_find_mmio_cache(
     return cache;
 }
 
+static void latch_linear_to_phys(struct hvm_vcpu_io *vio, unsigned long gla,
+                                 unsigned long gpa, bool_t write)
+{
+    if ( vio->mmio_access.gla_valid )
+        return;
+
+    vio->mmio_gva = gla & PAGE_MASK;
+    vio->mmio_gpfn = PFN_DOWN(gpa);
+    vio->mmio_access = (struct npfec){ .gla_valid = 1,
+                                       .read_access = 1,
+                                       .write_access = write };
+}
+
 static int hvmemul_linear_mmio_access(
     unsigned long gla, unsigned int size, uint8_t dir, void *buffer,
     uint32_t pfec, struct hvm_emulate_ctxt *hvmemul_ctxt, bool_t known_gpfn)
@@ -703,6 +716,8 @@ static int hvmemul_linear_mmio_access(
                                     hvmemul_ctxt);
         if ( rc != X86EMUL_OKAY )
             return rc;
+
+        latch_linear_to_phys(vio, gla, gpa, dir == IOREQ_WRITE);
     }
 
     for ( ;; )
--
generated by git-patchbot for /home/xen/git/xen.git#master

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