Some callers need the linear address (with appropriate segment base), whether
or not the limit or canonical check succeeds.
While modifying the function, change the return type to bool_t to match its
semantics.
Signed-off-by: Andrew Cooper <andrew.coop...@citrix.com>
Reviewed-by: Jan Beulich <jbeul...@suse.com>
---
CC: Wei Liu <wei.l...@citrix.com>
---
xen/arch/x86/hvm/hvm.c | 37 +++++++++++++++++++++++--------------
xen/include/asm-x86/hvm/hvm.h | 2 +-
2 files changed, 24 insertions(+), 15 deletions(-)
diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index 82e2ed1..863d134 100644
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -2411,7 +2411,7 @@ int hvm_set_cr4(unsigned long value, bool_t may_defer)
return X86EMUL_EXCEPTION;
}
-int hvm_virtual_to_linear_addr(
+bool_t hvm_virtual_to_linear_addr(
enum x86_segment seg,
struct segment_register *reg,
unsigned long offset,
@@ -2421,6 +2421,7 @@ int hvm_virtual_to_linear_addr(
unsigned long *linear_addr)
{
unsigned long addr = offset, last_byte;
+ bool_t okay = 0;
if ( !(current->arch.hvm_vcpu.guest_cr[0] & X86_CR0_PE) )
{
@@ -2431,7 +2432,7 @@ int hvm_virtual_to_linear_addr(
addr = (uint32_t)(addr + reg->base);
last_byte = (uint32_t)addr + bytes - !!bytes;
if ( last_byte < addr )
- return 0;
+ goto out;
}
else if ( addr_size != 64 )
{
@@ -2439,15 +2440,21 @@ int hvm_virtual_to_linear_addr(
* COMPATIBILITY MODE: Apply segment checks and add base.
*/
+ /*
+ * Hardware truncates to 32 bits in compatibility mode.
+ * It does not truncate to 16 bits in 16-bit address-size mode.
+ */
+ addr = (uint32_t)(addr + reg->base);
+
switch ( access_type )
{
case hvm_access_read:
if ( (reg->attr.fields.type & 0xa) == 0x8 )
- return 0; /* execute-only code segment */
+ goto out; /* execute-only code segment */
break;
case hvm_access_write:
if ( (reg->attr.fields.type & 0xa) != 0x2 )
- return 0; /* not a writable data segment */
+ goto out; /* not a writable data segment */
break;
default:
break;
@@ -2464,16 +2471,10 @@ int hvm_virtual_to_linear_addr(
/* Check first byte and last byte against respective bounds. */
if ( (offset <= reg->limit) || (last_byte < offset) )
- return 0;
+ goto out;
}
else if ( (last_byte > reg->limit) || (last_byte < offset) )
- return 0; /* last byte is beyond limit or wraps 0xFFFFFFFF */
-
- /*
- * Hardware truncates to 32 bits in compatibility mode.
- * It does not truncate to 16 bits in 16-bit address-size mode.
- */
- addr = (uint32_t)(addr + reg->base);
+ goto out; /* last byte is beyond limit or wraps 0xFFFFFFFF */
}
else
{
@@ -2487,11 +2488,19 @@ int hvm_virtual_to_linear_addr(
last_byte = addr + bytes - !!bytes;
if ( !is_canonical_address(addr) || last_byte < addr ||
!is_canonical_address(last_byte) )
- return 0;
+ goto out;
}
+ /* All checks ok. */
+ okay = 1;
+
+ out:
+ /*
+ * Always return the correct linear address, even if a permission check
+ * failed. The permissions failure is not relevant to some callers.
+ */
*linear_addr = addr;
- return 1;
+ return okay;
}
struct hvm_write_map {
diff --git a/xen/include/asm-x86/hvm/hvm.h b/xen/include/asm-x86/hvm/hvm.h
index 7b7ff3f..add6ee8 100644
--- a/xen/include/asm-x86/hvm/hvm.h
+++ b/xen/include/asm-x86/hvm/hvm.h
@@ -471,7 +471,7 @@ enum hvm_access_type {
hvm_access_read,
hvm_access_write
};
-int hvm_virtual_to_linear_addr(
+bool_t hvm_virtual_to_linear_addr(
enum x86_segment seg,
struct segment_register *reg,
unsigned long offset,
--
2.1.4
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