93 lines
3.1 KiB
Diff
93 lines
3.1 KiB
Diff
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# Commit 7f12732670b31b2fea899a4160d455574658474f
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# Date 2013-09-23 09:53:55 +0200
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# Author Jan Beulich <jbeulich@suse.com>
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# Committer Jan Beulich <jbeulich@suse.com>
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x86/HVM: linear address must be canonical for the whole accessed range
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... rather than just for the first byte.
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While at it, also
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- make the real mode case at least dpo a wrap around check
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- drop the mis-named "gpf" label (we're not generating faults here)
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and use in-place returns instead
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Signed-off-by: Jan Beulich <jbeulich@suse.com>
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Acked-by: Keir Fraser <keir@xen.org>
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--- a/xen/arch/x86/hvm/hvm.c
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+++ b/xen/arch/x86/hvm/hvm.c
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@@ -1938,8 +1938,7 @@ int hvm_virtual_to_linear_addr(
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unsigned int addr_size,
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unsigned long *linear_addr)
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{
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- unsigned long addr = offset;
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- uint32_t last_byte;
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+ unsigned long addr = offset, last_byte;
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if ( !(current->arch.hvm_vcpu.guest_cr[0] & X86_CR0_PE) )
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{
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@@ -1948,6 +1947,9 @@ int hvm_virtual_to_linear_addr(
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* Certain of them are not done in native real mode anyway.
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*/
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addr = (uint32_t)(addr + reg->base);
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+ last_byte = (uint32_t)addr + bytes - 1;
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+ if ( last_byte < addr )
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+ return 0;
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}
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else if ( addr_size != 64 )
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{
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@@ -1959,17 +1961,17 @@ int hvm_virtual_to_linear_addr(
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{
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case hvm_access_read:
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if ( (reg->attr.fields.type & 0xa) == 0x8 )
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- goto gpf; /* execute-only code segment */
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+ return 0; /* execute-only code segment */
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break;
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case hvm_access_write:
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if ( (reg->attr.fields.type & 0xa) != 0x2 )
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- goto gpf; /* not a writable data segment */
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+ return 0; /* not a writable data segment */
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break;
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default:
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break;
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}
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- last_byte = offset + bytes - 1;
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+ last_byte = (uint32_t)offset + bytes - 1;
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/* Is this a grows-down data segment? Special limit check if so. */
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if ( (reg->attr.fields.type & 0xc) == 0x4 )
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@@ -1980,10 +1982,10 @@ int hvm_virtual_to_linear_addr(
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/* Check first byte and last byte against respective bounds. */
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if ( (offset <= reg->limit) || (last_byte < offset) )
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- goto gpf;
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+ return 0;
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}
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else if ( (last_byte > reg->limit) || (last_byte < offset) )
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- goto gpf; /* last byte is beyond limit or wraps 0xFFFFFFFF */
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+ return 0; /* last byte is beyond limit or wraps 0xFFFFFFFF */
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/*
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* Hardware truncates to 32 bits in compatibility mode.
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@@ -2000,15 +2002,14 @@ int hvm_virtual_to_linear_addr(
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if ( (seg == x86_seg_fs) || (seg == x86_seg_gs) )
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addr += reg->base;
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- if ( !is_canonical_address(addr) )
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- goto gpf;
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+ last_byte = addr + bytes - 1;
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+ if ( !is_canonical_address(addr) || last_byte < addr ||
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+ !is_canonical_address(last_byte) )
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+ return 0;
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}
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*linear_addr = addr;
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return 1;
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-
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- gpf:
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- return 0;
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}
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/* On non-NULL return, we leave this function holding an additional
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