[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v4 17/17] x86/hvm: track large memory mapped accesses by buffer offset
The code in hvmemul_do_io() that tracks large reads or writes, to avoid re-issue of component I/O, is defeated by accesses across a page boundary because it uses physical address. The code is also only relevant to memory mapped I/O to or from a buffer. This patch re-factors the code and moves it into hvmemul_phys_mmio_access() where it is relevant and tracks using buffer offset rather then address. 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 | 98 ++++++++++++++++------------------------ xen/include/asm-x86/hvm/vcpu.h | 16 ++++--- 2 files changed, 48 insertions(+), 66 deletions(-) diff --git a/xen/arch/x86/hvm/emulate.c b/xen/arch/x86/hvm/emulate.c index aa68787..4424dfc 100644 --- a/xen/arch/x86/hvm/emulate.c +++ b/xen/arch/x86/hvm/emulate.c @@ -107,29 +107,6 @@ static int hvmemul_do_io( return X86EMUL_UNHANDLEABLE; } - if ( is_mmio && !data_is_addr ) - { - /* Part of a multi-cycle read or write? */ - if ( dir == IOREQ_WRITE ) - { - paddr_t pa = vio->mmio_large_write_pa; - unsigned int bytes = vio->mmio_large_write_bytes; - if ( (addr >= pa) && ((addr + size) <= (pa + bytes)) ) - return X86EMUL_OKAY; - } - else - { - paddr_t pa = vio->mmio_large_read_pa; - unsigned int bytes = vio->mmio_large_read_bytes; - if ( (addr >= pa) && ((addr + size) <= (pa + bytes)) ) - { - memcpy(p_data, &vio->mmio_large_read[addr - pa], - size); - return X86EMUL_OKAY; - } - } - } - switch ( vio->io_req.state ) { case STATE_IOREQ_NONE: @@ -209,33 +186,6 @@ static int hvmemul_do_io( memcpy(p_data, &p.data, size); } - if ( is_mmio && !data_is_addr ) - { - /* Part of a multi-cycle read or write? */ - if ( dir == IOREQ_WRITE ) - { - paddr_t pa = vio->mmio_large_write_pa; - unsigned int bytes = vio->mmio_large_write_bytes; - if ( bytes == 0 ) - pa = vio->mmio_large_write_pa = addr; - if ( addr == (pa + bytes) ) - vio->mmio_large_write_bytes += size; - } - else - { - paddr_t pa = vio->mmio_large_read_pa; - unsigned int bytes = vio->mmio_large_read_bytes; - if ( bytes == 0 ) - pa = vio->mmio_large_read_pa = addr; - if ( (addr == (pa + bytes)) && - ((bytes + size) <= sizeof(vio->mmio_large_read)) ) - { - memcpy(&vio->mmio_large_read[bytes], p_data, size); - vio->mmio_large_read_bytes += size; - } - } - } - return X86EMUL_OKAY; } @@ -601,8 +551,11 @@ static int hvmemul_virtual_to_linear( } static int hvmemul_phys_mmio_access( - paddr_t gpa, unsigned int size, uint8_t dir, uint8_t **buffer) + paddr_t gpa, unsigned int size, uint8_t dir, uint8_t *buffer, + unsigned int *off) { + struct vcpu *curr = current; + struct hvm_vcpu_io *vio = &curr->arch.hvm_vcpu.hvm_io; unsigned long one_rep = 1; unsigned int chunk; int rc; @@ -621,14 +574,41 @@ static int hvmemul_phys_mmio_access( for ( ;; ) { - rc = hvmemul_do_mmio_buffer(gpa, &one_rep, chunk, dir, 0, - *buffer); - if ( rc != X86EMUL_OKAY ) - break; + /* Have we already done this chunk? */ + if ( (*off + chunk) <= vio->mmio_cache[dir].size ) + { + ASSERT(*off + chunk <= vio->mmio_cache[dir].size); + + if ( dir == IOREQ_READ ) + memcpy(&buffer[*off], + &vio->mmio_cache[IOREQ_READ].buffer[*off], + chunk); + else + { + if ( memcmp(&buffer[*off], + &vio->mmio_cache[IOREQ_WRITE].buffer[*off], + chunk) != 0 ) + domain_crash(curr->domain); + } + } + else + { + ASSERT(*off == vio->mmio_cache[dir].size); + + rc = hvmemul_do_mmio_buffer(gpa, &one_rep, chunk, dir, 0, + &buffer[*off]); + if ( rc != X86EMUL_OKAY ) + break; + + /* Note that we have now done this chunk */ + memcpy(&vio->mmio_cache[dir].buffer[*off], + &buffer[*off], chunk); + vio->mmio_cache[dir].size += chunk; + } /* Advance to the next chunk */ gpa += chunk; - *buffer += chunk; + *off += chunk; size -= chunk; if ( size == 0 ) @@ -651,7 +631,7 @@ static int hvmemul_linear_mmio_access( { struct hvm_vcpu_io *vio = ¤t->arch.hvm_vcpu.hvm_io; unsigned long page_off = gla & (PAGE_SIZE - 1); - unsigned int chunk; + unsigned int chunk, buffer_off = 0; paddr_t gpa; unsigned long one_rep = 1; int rc; @@ -670,7 +650,7 @@ static int hvmemul_linear_mmio_access( for ( ;; ) { - rc = hvmemul_phys_mmio_access(gpa, chunk, dir, &buffer); + rc = hvmemul_phys_mmio_access(gpa, chunk, dir, buffer, &buffer_off); if ( rc != X86EMUL_OKAY ) break; @@ -1625,7 +1605,7 @@ static int _hvm_emulate_one(struct hvm_emulate_ctxt *hvmemul_ctxt, rc = X86EMUL_RETRY; if ( rc != X86EMUL_RETRY ) { - vio->mmio_large_read_bytes = vio->mmio_large_write_bytes = 0; + memset(&vio->mmio_cache, 0, sizeof(vio->mmio_cache)); vio->mmio_insn_bytes = 0; } else diff --git a/xen/include/asm-x86/hvm/vcpu.h b/xen/include/asm-x86/hvm/vcpu.h index 008c8fa..4f41c83 100644 --- a/xen/include/asm-x86/hvm/vcpu.h +++ b/xen/include/asm-x86/hvm/vcpu.h @@ -61,13 +61,15 @@ struct hvm_vcpu_io { unsigned long mmio_gva; unsigned long mmio_gpfn; - /* We may read up to m256 as a number of device-model transactions. */ - paddr_t mmio_large_read_pa; - uint8_t mmio_large_read[32]; - unsigned int mmio_large_read_bytes; - /* We may write up to m256 as a number of device-model transactions. */ - unsigned int mmio_large_write_bytes; - paddr_t mmio_large_write_pa; + /* + * We may read or write up to m256 as a number of device-model + * transactions. + */ + struct { + unsigned long size; + uint8_t buffer[32]; + } mmio_cache[2]; /* Indexed by ioreq type */ + /* For retries we shouldn't re-fetch the instruction. */ unsigned int mmio_insn_bytes; unsigned char mmio_insn[16]; -- 1.7.10.4 _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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