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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH 16/17] x86/hvm: remove multiple open coded 'chunking' loops
...in hvmemul_read/write()
Add hvmemul_phys_mmio_access() and hvmemul_linear_mmio_access() functions
to reduce code duplication.
Signed-off-by: Paul Durrant <paul.durrant@xxxxxxxxxx>
Cc: Keir Fraser <keir@xxxxxxx>
Cc: Jan Beulich <jbeulich@xxxxxxxx>
Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
xen/arch/x86/hvm/emulate.c | 237 +++++++++++++++++++++++++-------------------
1 file changed, 133 insertions(+), 104 deletions(-)
diff --git a/xen/arch/x86/hvm/emulate.c b/xen/arch/x86/hvm/emulate.c
index 46fab98..8b9b7f2 100644
--- a/xen/arch/x86/hvm/emulate.c
+++ b/xen/arch/x86/hvm/emulate.c
@@ -599,6 +599,124 @@ static int hvmemul_virtual_to_linear(
return X86EMUL_EXCEPTION;
}
+static int hvmemul_phys_mmio_access(paddr_t mmio_addr,
+ unsigned int size,
+ uint8_t dir,
+ void *buffer)
+{
+ unsigned long one_rep = 1;
+ paddr_t page_off = mmio_addr & (PAGE_SIZE - 1);
+ unsigned int chunk;
+ int rc = 0;
+
+ /* Accesses must fall within a page */
+ if (page_off + size > PAGE_SIZE)
+ return X86EMUL_UNHANDLEABLE;
+
+ /*
+ * hvmemul_do_io() cannot handle non-power-of-2 accesses or
+ * accesses larger than sizeof(long), so choose the highest power
+ * of 2 not exceeding sizeof(long) as the 'chunk' size.
+ */
+ chunk = 1 << (fls(size) - 1);
+ if ( chunk > sizeof (long) )
+ chunk = sizeof (long);
+
+ while ( size != 0 )
+ {
+ rc = hvmemul_do_mmio_buffer(mmio_addr, &one_rep, chunk, dir, 0,
+ buffer);
+ if ( rc != X86EMUL_OKAY )
+ break;
+
+ /* Advance to the next chunk */
+ mmio_addr += chunk;
+ buffer += chunk;
+ size -= chunk;
+
+ /*
+ * If the chunk now exceeds the remaining size, choose the next
+ * lowest power of 2 that will fit.
+ */
+ while ( chunk > size )
+ chunk >>= 1;
+ }
+
+ return rc;
+}
+
+static int hvmemul_phys_mmio_read(paddr_t mmio_addr,
+ unsigned int size,
+ void *buffer)
+{
+ return hvmemul_phys_mmio_access(mmio_addr, size, IOREQ_READ, buffer);
+}
+
+static int hvmemul_phys_mmio_write(paddr_t mmio_addr,
+ unsigned int size,
+ void *buffer)
+{
+ return hvmemul_phys_mmio_access(mmio_addr, size, IOREQ_WRITE, buffer);
+}
+
+static int hvmemul_linear_mmio_access(unsigned long mmio_addr,
+ unsigned int size,
+ uint8_t dir,
+ void *buffer,
+ uint32_t pfec,
+ struct hvm_emulate_ctxt *hvmemul_ctxt)
+{
+ unsigned long page_off = mmio_addr & (PAGE_SIZE - 1);
+ unsigned int chunk;
+ paddr_t gpa;
+ unsigned long one_rep = 1;
+ int rc;
+
+ chunk = min_t(unsigned int, size, PAGE_SIZE - page_off);
+ rc = hvmemul_linear_to_phys(mmio_addr, &gpa, chunk,
+ &one_rep, pfec, hvmemul_ctxt);
+ while ( rc == X86EMUL_OKAY )
+ {
+ rc = hvmemul_phys_mmio_access(gpa, chunk, dir, buffer);
+ if ( rc != X86EMUL_OKAY )
+ break;
+
+ mmio_addr += chunk;
+ ASSERT((mmio_addr & (PAGE_SIZE - 1)) == 0);
+ buffer += chunk;
+ size -= chunk;
+
+ if ( size == 0 )
+ break;
+
+ chunk = min_t(unsigned int, size, PAGE_SIZE);
+ rc = hvmemul_linear_to_phys(mmio_addr, &gpa, chunk,
+ &one_rep, pfec, hvmemul_ctxt);
+ }
+
+ return rc;
+}
+
+static int hvmemul_linear_mmio_read(unsigned long mmio_addr,
+ unsigned int size,
+ void *buffer,
+ uint32_t pfec,
+ struct hvm_emulate_ctxt *hvmemul_ctxt)
+{
+ return hvmemul_linear_mmio_access(mmio_addr, size, IOREQ_READ, buffer,
+ pfec, hvmemul_ctxt);
+}
+
+static int hvmemul_linear_mmio_write(unsigned long mmio_addr,
+ unsigned int size,
+ void *buffer,
+ uint32_t pfec,
+ struct hvm_emulate_ctxt *hvmemul_ctxt)
+{
+ return hvmemul_linear_mmio_access(mmio_addr, size, IOREQ_WRITE, buffer,
+ pfec, hvmemul_ctxt);
+}
+
static int __hvmemul_read(
enum x86_segment seg,
unsigned long offset,
@@ -608,52 +726,26 @@ static int __hvmemul_read(
struct hvm_emulate_ctxt *hvmemul_ctxt)
{
struct vcpu *curr = current;
- unsigned long addr, reps = 1;
- unsigned int off, chunk = min(bytes, 1U << LONG_BYTEORDER);
+ unsigned long addr, one_rep = 1;
uint32_t pfec = PFEC_page_present;
struct hvm_vcpu_io *vio = &curr->arch.hvm_vcpu.hvm_io;
paddr_t gpa;
int rc;
rc = hvmemul_virtual_to_linear(
- seg, offset, bytes, &reps, access_type, hvmemul_ctxt, &addr);
+ seg, offset, bytes, &one_rep, access_type, hvmemul_ctxt, &addr);
if ( rc != X86EMUL_OKAY )
return rc;
- off = addr & (PAGE_SIZE - 1);
- /*
- * We only need to handle sizes actual instruction operands can have. All
- * such sizes are either powers of 2 or the sum of two powers of 2. Thus
- * picking as initial chunk size the largest power of 2 not greater than
- * the total size will always result in only power-of-2 size requests
- * issued to hvmemul_do_mmio() (hvmemul_do_io() rejects non-powers-of-2).
- */
- while ( chunk & (chunk - 1) )
- chunk &= chunk - 1;
- if ( off + bytes > PAGE_SIZE )
- while ( off & (chunk - 1) )
- chunk >>= 1;
if ( ((access_type != hvm_access_insn_fetch
? vio->mmio_access.read_access
: vio->mmio_access.insn_fetch)) &&
(vio->mmio_gva == (addr & PAGE_MASK)) )
{
- gpa = (((paddr_t)vio->mmio_gpfn << PAGE_SHIFT) | off);
- while ( (off + chunk) <= PAGE_SIZE )
- {
- rc = hvmemul_do_mmio_buffer(gpa, &reps, chunk, IOREQ_READ, 0,
- p_data);
- if ( rc != X86EMUL_OKAY || bytes == chunk )
- return rc;
- off += chunk;
- gpa += chunk;
- p_data += chunk;
- bytes -= chunk;
- if ( bytes < chunk )
- chunk = bytes;
- }
+ gpa = (((paddr_t)vio->mmio_gpfn << PAGE_SHIFT) |
+ (addr & (PAGE_SIZE - 1)));
- return X86EMUL_UNHANDLEABLE;
+ return hvmemul_phys_mmio_read(gpa, bytes, p_data);
}
if ( (seg != x86_seg_none) &&
@@ -673,30 +765,9 @@ static int __hvmemul_read(
case HVMCOPY_bad_gfn_to_mfn:
if ( access_type == hvm_access_insn_fetch )
return X86EMUL_UNHANDLEABLE;
- rc = hvmemul_linear_to_phys(addr, &gpa, chunk, &reps, pfec,
- hvmemul_ctxt);
- while ( rc == X86EMUL_OKAY )
- {
- rc = hvmemul_do_mmio_buffer(gpa, &reps, chunk, IOREQ_READ, 0,
- p_data);
- if ( rc != X86EMUL_OKAY || bytes == chunk )
- break;
- addr += chunk;
- off += chunk;
- p_data += chunk;
- bytes -= chunk;
- if ( bytes < chunk )
- chunk = bytes;
- if ( off < PAGE_SIZE )
- gpa += chunk;
- else
- {
- rc = hvmemul_linear_to_phys(addr, &gpa, chunk, &reps, pfec,
- hvmemul_ctxt);
- off = 0;
- }
- }
- return rc;
+
+ return hvmemul_linear_mmio_read(addr, bytes, p_data,
+ pfec, hvmemul_ctxt);
case HVMCOPY_gfn_paged_out:
case HVMCOPY_gfn_shared:
return X86EMUL_RETRY;
@@ -761,44 +832,24 @@ static int hvmemul_write(
struct hvm_emulate_ctxt *hvmemul_ctxt =
container_of(ctxt, struct hvm_emulate_ctxt, ctxt);
struct vcpu *curr = current;
- unsigned long addr, reps = 1;
- unsigned int off, chunk = min(bytes, 1U << LONG_BYTEORDER);
+ unsigned long addr, one_rep = 1;
uint32_t pfec = PFEC_page_present | PFEC_write_access;
struct hvm_vcpu_io *vio = &curr->arch.hvm_vcpu.hvm_io;
paddr_t gpa;
int rc;
rc = hvmemul_virtual_to_linear(
- seg, offset, bytes, &reps, hvm_access_write, hvmemul_ctxt, &addr);
+ seg, offset, bytes, &one_rep, hvm_access_write, hvmemul_ctxt, &addr);
if ( rc != X86EMUL_OKAY )
return rc;
- off = addr & (PAGE_SIZE - 1);
- /* See the respective comment in __hvmemul_read(). */
- while ( chunk & (chunk - 1) )
- chunk &= chunk - 1;
- if ( off + bytes > PAGE_SIZE )
- while ( off & (chunk - 1) )
- chunk >>= 1;
if ( vio->mmio_access.write_access &&
(vio->mmio_gva == (addr & PAGE_MASK)) )
{
- gpa = (((paddr_t)vio->mmio_gpfn << PAGE_SHIFT) | off);
- while ( (off + chunk) <= PAGE_SIZE )
- {
- rc = hvmemul_do_mmio_buffer(gpa, &reps, chunk, IOREQ_WRITE, 0,
- p_data);
- if ( rc != X86EMUL_OKAY || bytes == chunk )
- return rc;
- off += chunk;
- gpa += chunk;
- p_data += chunk;
- bytes -= chunk;
- if ( bytes < chunk )
- chunk = bytes;
- }
+ gpa = (((paddr_t)vio->mmio_gpfn << PAGE_SHIFT) |
+ (addr & (PAGE_SIZE - 1)));
- return X86EMUL_UNHANDLEABLE;
+ return hvmemul_phys_mmio_write(gpa, bytes, p_data);
}
if ( (seg != x86_seg_none) &&
@@ -814,30 +865,8 @@ static int hvmemul_write(
case HVMCOPY_bad_gva_to_gfn:
return X86EMUL_EXCEPTION;
case HVMCOPY_bad_gfn_to_mfn:
- rc = hvmemul_linear_to_phys(addr, &gpa, chunk, &reps, pfec,
- hvmemul_ctxt);
- while ( rc == X86EMUL_OKAY )
- {
- rc = hvmemul_do_mmio_buffer(gpa, &reps, chunk, IOREQ_WRITE, 0,
- p_data);
- if ( rc != X86EMUL_OKAY || bytes == chunk )
- break;
- addr += chunk;
- off += chunk;
- p_data += chunk;
- bytes -= chunk;
- if ( bytes < chunk )
- chunk = bytes;
- if ( off < PAGE_SIZE )
- gpa += chunk;
- else
- {
- rc = hvmemul_linear_to_phys(addr, &gpa, chunk, &reps, pfec,
- hvmemul_ctxt);
- off = 0;
- }
- }
- return rc;
+ return hvmemul_linear_mmio_write(addr, bytes, p_data,
+ pfec, hvmemul_ctxt);
case HVMCOPY_gfn_paged_out:
case HVMCOPY_gfn_shared:
return X86EMUL_RETRY;
--
1.7.10.4
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