diff options
| -rw-r--r-- | xen/arch/x86/hvm/emulate.c | 115 |
1 files changed, 95 insertions, 20 deletions
diff --git a/xen/arch/x86/hvm/emulate.c b/xen/arch/x86/hvm/emulate.c index 9bfba483ba..4ce4e0c5f0 100644 --- a/xen/arch/x86/hvm/emulate.c +++ b/xen/arch/x86/hvm/emulate.c @@ -438,6 +438,7 @@ static int __hvmemul_read( { struct vcpu *curr = current; unsigned long addr, reps = 1; + unsigned int off, chunk = min(bytes, 1U << LONG_BYTEORDER); uint32_t pfec = PFEC_page_present; struct hvm_vcpu_io *vio = &curr->arch.hvm_vcpu.hvm_io; paddr_t gpa; @@ -447,16 +448,38 @@ static int __hvmemul_read( seg, offset, bytes, &reps, 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 ( unlikely(vio->mmio_gva == (addr & PAGE_MASK)) && vio->mmio_gva ) { - unsigned int off = addr & (PAGE_SIZE - 1); if ( access_type == hvm_access_insn_fetch ) return X86EMUL_UNHANDLEABLE; gpa = (((paddr_t)vio->mmio_gpfn << PAGE_SHIFT) | off); - if ( (off + bytes) <= PAGE_SIZE ) - return hvmemul_do_mmio(gpa, &reps, bytes, 0, - IOREQ_READ, 0, p_data); + while ( (off + chunk) <= PAGE_SIZE ) + { + rc = hvmemul_do_mmio(gpa, &reps, chunk, 0, IOREQ_READ, 0, p_data); + if ( rc != X86EMUL_OKAY || bytes == chunk ) + return rc; + addr += chunk; + off += chunk; + gpa += chunk; + p_data += chunk; + bytes -= chunk; + if ( bytes < chunk ) + chunk = bytes; + } } if ( (seg != x86_seg_none) && @@ -473,14 +496,32 @@ static int __hvmemul_read( return X86EMUL_EXCEPTION; case HVMCOPY_unhandleable: return X86EMUL_UNHANDLEABLE; - case HVMCOPY_bad_gfn_to_mfn: + case HVMCOPY_bad_gfn_to_mfn: if ( access_type == hvm_access_insn_fetch ) return X86EMUL_UNHANDLEABLE; - rc = hvmemul_linear_to_phys( - addr, &gpa, bytes, &reps, pfec, hvmemul_ctxt); - if ( rc != X86EMUL_OKAY ) - return rc; - return hvmemul_do_mmio(gpa, &reps, bytes, 0, IOREQ_READ, 0, p_data); + rc = hvmemul_linear_to_phys(addr, &gpa, chunk, &reps, pfec, + hvmemul_ctxt); + while ( rc == X86EMUL_OKAY ) + { + rc = hvmemul_do_mmio(gpa, &reps, chunk, 0, 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; case HVMCOPY_gfn_paged_out: return X86EMUL_RETRY; case HVMCOPY_gfn_shared: @@ -537,6 +578,7 @@ static int hvmemul_write( 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); uint32_t pfec = PFEC_page_present | PFEC_write_access; struct hvm_vcpu_io *vio = &curr->arch.hvm_vcpu.hvm_io; paddr_t gpa; @@ -546,14 +588,30 @@ static int hvmemul_write( seg, offset, bytes, &reps, 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 ( unlikely(vio->mmio_gva == (addr & PAGE_MASK)) && vio->mmio_gva ) { - unsigned int off = addr & (PAGE_SIZE - 1); gpa = (((paddr_t)vio->mmio_gpfn << PAGE_SHIFT) | off); - if ( (off + bytes) <= PAGE_SIZE ) - return hvmemul_do_mmio(gpa, &reps, bytes, 0, - IOREQ_WRITE, 0, p_data); + while ( (off + chunk) <= PAGE_SIZE ) + { + rc = hvmemul_do_mmio(gpa, &reps, chunk, 0, IOREQ_WRITE, 0, p_data); + if ( rc != X86EMUL_OKAY || bytes == chunk ) + return rc; + addr += chunk; + off += chunk; + gpa += chunk; + p_data += chunk; + bytes -= chunk; + if ( bytes < chunk ) + chunk = bytes; + } } if ( (seg != x86_seg_none) && @@ -569,12 +627,29 @@ static int hvmemul_write( case HVMCOPY_unhandleable: return X86EMUL_UNHANDLEABLE; case HVMCOPY_bad_gfn_to_mfn: - rc = hvmemul_linear_to_phys( - addr, &gpa, bytes, &reps, pfec, hvmemul_ctxt); - if ( rc != X86EMUL_OKAY ) - return rc; - return hvmemul_do_mmio(gpa, &reps, bytes, 0, - IOREQ_WRITE, 0, p_data); + rc = hvmemul_linear_to_phys(addr, &gpa, chunk, &reps, pfec, + hvmemul_ctxt); + while ( rc == X86EMUL_OKAY ) + { + rc = hvmemul_do_mmio(gpa, &reps, chunk, 0, 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; case HVMCOPY_gfn_paged_out: return X86EMUL_RETRY; case HVMCOPY_gfn_shared: |