[Xen-devel] [PATCH RFC v2 1/2] x86/emulate: Move hvmemul_linear_to_phys

[Alexandru Stefan ISAILA <aisaila@xxxxxxxxxxxxxxx>]

This is done so hvmemul_linear_to_phys() can be called from
hvmemul_map_linear_addr()

Signed-off-by: Alexandru Isaila <aisaila@xxxxxxxxxxxxxxx>
---
 xen/arch/x86/hvm/emulate.c | 181 ++++++++++++++++++-------------------
 1 file changed, 90 insertions(+), 91 deletions(-)

diff --git a/xen/arch/x86/hvm/emulate.c b/xen/arch/x86/hvm/emulate.c
index 2d02ef1521..a766eecc8e 100644
--- a/xen/arch/x86/hvm/emulate.c
+++ b/xen/arch/x86/hvm/emulate.c
@@ -530,6 +530,95 @@ static int hvmemul_do_mmio_addr(paddr_t mmio_gpa,
     return hvmemul_do_io_addr(1, mmio_gpa, reps, size, dir, df, ram_gpa);
 }
 
+/*
+ * Convert addr from linear to physical form, valid over the range
+ * [addr, addr + *reps * bytes_per_rep]. *reps is adjusted according to
+ * the valid computed range. It is always >0 when X86EMUL_OKAY is returned.
+ * @pfec indicates the access checks to be performed during page-table walks.
+ */
+static int hvmemul_linear_to_phys(
+    unsigned long addr,
+    paddr_t *paddr,
+    unsigned int bytes_per_rep,
+    unsigned long *reps,
+    uint32_t pfec,
+    struct hvm_emulate_ctxt *hvmemul_ctxt)
+{
+    struct vcpu *curr = current;
+    unsigned long pfn, npfn, done, todo, i, offset = addr & ~PAGE_MASK;
+    int reverse;
+
+    /*
+     * Clip repetitions to a sensible maximum. This avoids extensive looping in
+     * this function while still amortising the cost of I/O trap-and-emulate.
+     */
+    *reps = min_t(unsigned long, *reps, 4096);
+
+    /* With no paging it's easy: linear == physical. */
+    if ( !(curr->arch.hvm.guest_cr[0] & X86_CR0_PG) )
+    {
+        *paddr = addr;
+        return X86EMUL_OKAY;
+    }
+
+    /* Reverse mode if this is a backwards multi-iteration string operation. */
+    reverse = (hvmemul_ctxt->ctxt.regs->eflags & X86_EFLAGS_DF) && (*reps > 1);
+
+    if ( reverse && ((PAGE_SIZE - offset) < bytes_per_rep) )
+    {
+        /* Do page-straddling first iteration forwards via recursion. */
+        paddr_t _paddr;
+        unsigned long one_rep = 1;
+        int rc = hvmemul_linear_to_phys(
+            addr, &_paddr, bytes_per_rep, &one_rep, pfec, hvmemul_ctxt);
+        if ( rc != X86EMUL_OKAY )
+            return rc;
+        pfn = _paddr >> PAGE_SHIFT;
+    }
+    else if ( (pfn = paging_gva_to_gfn(curr, addr, &pfec)) == 
gfn_x(INVALID_GFN) )
+    {
+        if ( pfec & (PFEC_page_paged | PFEC_page_shared) )
+            return X86EMUL_RETRY;
+        *reps = 0;
+        x86_emul_pagefault(pfec, addr, &hvmemul_ctxt->ctxt);
+        return X86EMUL_EXCEPTION;
+    }
+
+    done = reverse ? bytes_per_rep + offset : PAGE_SIZE - offset;
+    todo = *reps * bytes_per_rep;
+    for ( i = 1; done < todo; i++ )
+    {
+        /* Get the next PFN in the range. */
+        addr += reverse ? -PAGE_SIZE : PAGE_SIZE;
+        npfn = paging_gva_to_gfn(curr, addr, &pfec);
+
+        /* Is it contiguous with the preceding PFNs? If not then we're done. */
+        if ( (npfn == gfn_x(INVALID_GFN)) ||
+             (npfn != (pfn + (reverse ? -i : i))) )
+        {
+            if ( pfec & (PFEC_page_paged | PFEC_page_shared) )
+                return X86EMUL_RETRY;
+            done /= bytes_per_rep;
+            if ( done == 0 )
+            {
+                ASSERT(!reverse);
+                if ( npfn != gfn_x(INVALID_GFN) )
+                    return X86EMUL_UNHANDLEABLE;
+                *reps = 0;
+                x86_emul_pagefault(pfec, addr & PAGE_MASK, 
&hvmemul_ctxt->ctxt);
+                return X86EMUL_EXCEPTION;
+            }
+            *reps = done;
+            break;
+        }
+
+        done += PAGE_SIZE;
+    }
+
+    *paddr = ((paddr_t)pfn << PAGE_SHIFT) | offset;
+    return X86EMUL_OKAY;
+}
+
 /*
  * Map the frame(s) covering an individual linear access, for writeable
  * access.  May return NULL for MMIO, or ERR_PTR(~X86EMUL_*) for other errors
@@ -692,97 +781,7 @@ static void hvmemul_unmap_linear_addr(
         *mfn++ = _mfn(0);
     }
 #endif
-}
-
-/*
- * Convert addr from linear to physical form, valid over the range
- * [addr, addr + *reps * bytes_per_rep]. *reps is adjusted according to
- * the valid computed range. It is always >0 when X86EMUL_OKAY is returned.
- * @pfec indicates the access checks to be performed during page-table walks.
- */
-static int hvmemul_linear_to_phys(
-    unsigned long addr,
-    paddr_t *paddr,
-    unsigned int bytes_per_rep,
-    unsigned long *reps,
-    uint32_t pfec,
-    struct hvm_emulate_ctxt *hvmemul_ctxt)
-{
-    struct vcpu *curr = current;
-    unsigned long pfn, npfn, done, todo, i, offset = addr & ~PAGE_MASK;
-    int reverse;
-
-    /*
-     * Clip repetitions to a sensible maximum. This avoids extensive looping in
-     * this function while still amortising the cost of I/O trap-and-emulate.
-     */
-    *reps = min_t(unsigned long, *reps, 4096);
-
-    /* With no paging it's easy: linear == physical. */
-    if ( !(curr->arch.hvm.guest_cr[0] & X86_CR0_PG) )
-    {
-        *paddr = addr;
-        return X86EMUL_OKAY;
-    }
-
-    /* Reverse mode if this is a backwards multi-iteration string operation. */
-    reverse = (hvmemul_ctxt->ctxt.regs->eflags & X86_EFLAGS_DF) && (*reps > 1);
-
-    if ( reverse && ((PAGE_SIZE - offset) < bytes_per_rep) )
-    {
-        /* Do page-straddling first iteration forwards via recursion. */
-        paddr_t _paddr;
-        unsigned long one_rep = 1;
-        int rc = hvmemul_linear_to_phys(
-            addr, &_paddr, bytes_per_rep, &one_rep, pfec, hvmemul_ctxt);
-        if ( rc != X86EMUL_OKAY )
-            return rc;
-        pfn = _paddr >> PAGE_SHIFT;
-    }
-    else if ( (pfn = paging_gva_to_gfn(curr, addr, &pfec)) == 
gfn_x(INVALID_GFN) )
-    {
-        if ( pfec & (PFEC_page_paged | PFEC_page_shared) )
-            return X86EMUL_RETRY;
-        *reps = 0;
-        x86_emul_pagefault(pfec, addr, &hvmemul_ctxt->ctxt);
-        return X86EMUL_EXCEPTION;
-    }
-
-    done = reverse ? bytes_per_rep + offset : PAGE_SIZE - offset;
-    todo = *reps * bytes_per_rep;
-    for ( i = 1; done < todo; i++ )
-    {
-        /* Get the next PFN in the range. */
-        addr += reverse ? -PAGE_SIZE : PAGE_SIZE;
-        npfn = paging_gva_to_gfn(curr, addr, &pfec);
-
-        /* Is it contiguous with the preceding PFNs? If not then we're done. */
-        if ( (npfn == gfn_x(INVALID_GFN)) ||
-             (npfn != (pfn + (reverse ? -i : i))) )
-        {
-            if ( pfec & (PFEC_page_paged | PFEC_page_shared) )
-                return X86EMUL_RETRY;
-            done /= bytes_per_rep;
-            if ( done == 0 )
-            {
-                ASSERT(!reverse);
-                if ( npfn != gfn_x(INVALID_GFN) )
-                    return X86EMUL_UNHANDLEABLE;
-                *reps = 0;
-                x86_emul_pagefault(pfec, addr & PAGE_MASK, 
&hvmemul_ctxt->ctxt);
-                return X86EMUL_EXCEPTION;
-            }
-            *reps = done;
-            break;
-        }
-
-        done += PAGE_SIZE;
-    }
-
-    *paddr = ((paddr_t)pfn << PAGE_SHIFT) | offset;
-    return X86EMUL_OKAY;
-}
-    
+}  
 
 static int hvmemul_virtual_to_linear(
     enum x86_segment seg,
-- 
2.17.1


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