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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v4 01/17] x86/hvm: simplify hvmemul_do_io()
Currently hvmemul_do_io() handles paging for I/O to/from a guest address
inline. This causes every exit point to have to execute:
if ( ram_page )
put_page(ram_page);
This patch introduces wrapper hvmemul_do_io_addr() and
hvmemul_do_io_buffer() functions. The latter is used for I/O to/from a Xen
buffer and thus the complexity of paging can be restricted only to the
former, making the common hvmemul_do_io() function less convoluted.
This patch also tightens up some types and introduces pio/mmio wrappers
for the above functions with comments to document their semantics.
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 | 278 ++++++++++++++++++++++++-------------
xen/arch/x86/hvm/io.c | 4 +-
xen/include/asm-x86/hvm/emulate.h | 17 ++-
3 files changed, 198 insertions(+), 101 deletions(-)
diff --git a/xen/arch/x86/hvm/emulate.c b/xen/arch/x86/hvm/emulate.c
index ac9c9d6..9d7af0c 100644
--- a/xen/arch/x86/hvm/emulate.c
+++ b/xen/arch/x86/hvm/emulate.c
@@ -51,41 +51,23 @@ static void hvmtrace_io_assist(int is_mmio, ioreq_t *p)
}
static int hvmemul_do_io(
- int is_mmio, paddr_t addr, unsigned long *reps, int size,
- paddr_t ram_gpa, int dir, int df, void *p_data)
+ bool_t is_mmio, paddr_t addr, unsigned long *reps, unsigned int size,
+ uint8_t dir, bool_t df, bool_t data_is_addr, uintptr_t data)
{
struct vcpu *curr = current;
- struct hvm_vcpu_io *vio;
+ struct hvm_vcpu_io *vio = &curr->arch.hvm_vcpu.hvm_io;
ioreq_t p = {
.type = is_mmio ? IOREQ_TYPE_COPY : IOREQ_TYPE_PIO,
.addr = addr,
.size = size,
.dir = dir,
.df = df,
- .data = ram_gpa,
- .data_is_ptr = (p_data == NULL),
+ .data = data,
+ .data_is_ptr = data_is_addr, /* ioreq_t field name is misleading */
};
- unsigned long ram_gfn = paddr_to_pfn(ram_gpa);
- p2m_type_t p2mt;
- struct page_info *ram_page;
+ void *p_data = (void *)data;
int rc;
- /* Check for paged out page */
- ram_page = get_page_from_gfn(curr->domain, ram_gfn, &p2mt, P2M_UNSHARE);
- if ( p2m_is_paging(p2mt) )
- {
- if ( ram_page )
- put_page(ram_page);
- p2m_mem_paging_populate(curr->domain, ram_gfn);
- return X86EMUL_RETRY;
- }
- if ( p2m_is_shared(p2mt) )
- {
- if ( ram_page )
- put_page(ram_page);
- return X86EMUL_RETRY;
- }
-
/*
* Weird-sized accesses have undefined behaviour: we discard writes
* and read all-ones.
@@ -93,23 +75,10 @@ static int hvmemul_do_io(
if ( unlikely((size > sizeof(long)) || (size & (size - 1))) )
{
gdprintk(XENLOG_WARNING, "bad mmio size %d\n", size);
- ASSERT(p_data != NULL); /* cannot happen with a REP prefix */
- if ( dir == IOREQ_READ )
- memset(p_data, ~0, size);
- if ( ram_page )
- put_page(ram_page);
return X86EMUL_UNHANDLEABLE;
}
- if ( !p.data_is_ptr && (dir == IOREQ_WRITE) )
- {
- memcpy(&p.data, p_data, size);
- p_data = NULL;
- }
-
- vio = &curr->arch.hvm_vcpu.hvm_io;
-
- if ( is_mmio && !p.data_is_ptr )
+ if ( is_mmio && !data_is_addr )
{
/* Part of a multi-cycle read or write? */
if ( dir == IOREQ_WRITE )
@@ -117,11 +86,7 @@ static int hvmemul_do_io(
paddr_t pa = vio->mmio_large_write_pa;
unsigned int bytes = vio->mmio_large_write_bytes;
if ( (addr >= pa) && ((addr + size) <= (pa + bytes)) )
- {
- if ( ram_page )
- put_page(ram_page);
return X86EMUL_OKAY;
- }
}
else
{
@@ -131,8 +96,6 @@ static int hvmemul_do_io(
{
memcpy(p_data, &vio->mmio_large_read[addr - pa],
size);
- if ( ram_page )
- put_page(ram_page);
return X86EMUL_OKAY;
}
}
@@ -144,40 +107,28 @@ static int hvmemul_do_io(
break;
case HVMIO_completed:
vio->io_state = HVMIO_none;
- if ( p_data == NULL )
- {
- if ( ram_page )
- put_page(ram_page);
+ if ( data_is_addr || dir == IOREQ_WRITE )
return X86EMUL_UNHANDLEABLE;
- }
goto finish_access;
case HVMIO_dispatched:
/* May have to wait for previous cycle of a multi-write to complete. */
- if ( is_mmio && !p.data_is_ptr && (dir == IOREQ_WRITE) &&
+ if ( is_mmio && !data_is_addr && (dir == IOREQ_WRITE) &&
(addr == (vio->mmio_large_write_pa +
vio->mmio_large_write_bytes)) )
- {
- if ( ram_page )
- put_page(ram_page);
return X86EMUL_RETRY;
- }
/* fallthrough */
default:
- if ( ram_page )
- put_page(ram_page);
return X86EMUL_UNHANDLEABLE;
}
if ( hvm_io_pending(curr) )
{
gdprintk(XENLOG_WARNING, "WARNING: io already pending?\n");
- if ( ram_page )
- put_page(ram_page);
return X86EMUL_UNHANDLEABLE;
}
- vio->io_state =
- (p_data == NULL) ? HVMIO_dispatched : HVMIO_awaiting_completion;
+ vio->io_state = (data_is_addr || dir == IOREQ_WRITE) ?
+ HVMIO_dispatched : HVMIO_awaiting_completion;
vio->io_size = size;
/*
@@ -190,7 +141,12 @@ static int hvmemul_do_io(
p.count = *reps;
if ( dir == IOREQ_WRITE )
+ {
+ if ( !data_is_addr )
+ memcpy(&p.data, p_data, size);
+
hvmtrace_io_assist(is_mmio, &p);
+ }
if ( is_mmio )
{
@@ -235,7 +191,7 @@ static int hvmemul_do_io(
rc = X86EMUL_RETRY;
if ( !hvm_send_assist_req(s, &p) )
vio->io_state = HVMIO_none;
- else if ( p_data == NULL )
+ else if ( data_is_addr || dir == IOREQ_WRITE )
rc = X86EMUL_OKAY;
}
break;
@@ -245,20 +201,18 @@ static int hvmemul_do_io(
}
if ( rc != X86EMUL_OKAY )
- {
- if ( ram_page )
- put_page(ram_page);
return rc;
- }
finish_access:
if ( dir == IOREQ_READ )
+ {
hvmtrace_io_assist(is_mmio, &p);
- if ( p_data != NULL )
- memcpy(p_data, &vio->io_data, size);
+ if ( !data_is_addr )
+ memcpy(p_data, &vio->io_data, size);
+ }
- if ( is_mmio && !p.data_is_ptr )
+ if ( is_mmio && !data_is_addr )
{
/* Part of a multi-cycle read or write? */
if ( dir == IOREQ_WRITE )
@@ -285,23 +239,153 @@ static int hvmemul_do_io(
}
}
- if ( ram_page )
- put_page(ram_page);
return X86EMUL_OKAY;
}
-int hvmemul_do_pio(
- unsigned long port, unsigned long *reps, int size,
- paddr_t ram_gpa, int dir, int df, void *p_data)
+static int hvmemul_do_io_buffer(
+ bool_t is_mmio, paddr_t addr, unsigned long *reps, unsigned int size,
+ uint8_t dir, bool_t df, void *buffer)
+{
+ int rc;
+
+ BUG_ON(buffer == NULL);
+
+ rc = hvmemul_do_io(is_mmio, addr, reps, size, dir, df, 0,
+ (uintptr_t)buffer);
+ if ( rc == X86EMUL_UNHANDLEABLE && dir == IOREQ_READ )
+ memset(buffer, 0xff, size);
+
+ return rc;
+}
+
+static int hvmemul_acquire_page(unsigned long gmfn, struct page_info **page)
+{
+ struct domain *curr_d = current->domain;
+ p2m_type_t p2mt;
+
+ *page = get_page_from_gfn(curr_d, gmfn, &p2mt, P2M_UNSHARE);
+
+ if ( *page == NULL )
+ return X86EMUL_UNHANDLEABLE;
+
+ if ( p2m_is_paging(p2mt) )
+ {
+ put_page(*page);
+ p2m_mem_paging_populate(curr_d, gmfn);
+ return X86EMUL_RETRY;
+ }
+
+ if ( p2m_is_shared(p2mt) )
+ {
+ put_page(*page);
+ return X86EMUL_RETRY;
+ }
+
+ return X86EMUL_OKAY;
+}
+
+static inline void hvmemul_release_page(struct page_info *page)
{
- return hvmemul_do_io(0, port, reps, size, ram_gpa, dir, df, p_data);
+ put_page(page);
}
-static int hvmemul_do_mmio(
- paddr_t gpa, unsigned long *reps, int size,
- paddr_t ram_gpa, int dir, int df, void *p_data)
+static int hvmemul_do_io_addr(
+ bool_t is_mmio, paddr_t addr, unsigned long *reps,
+ unsigned int size, uint8_t dir, bool_t df, paddr_t ram_gpa)
+{
+ struct page_info *ram_page;
+ int rc;
+
+ rc = hvmemul_acquire_page(paddr_to_pfn(ram_gpa), &ram_page);
+ if ( rc != X86EMUL_OKAY )
+ return rc;
+
+ rc = hvmemul_do_io(is_mmio, addr, reps, size, dir, df, 1,
+ ram_gpa);
+
+ hvmemul_release_page(ram_page);
+
+ return rc;
+}
+
+/*
+ * Perform I/O between <port> and <buffer>. <dir> indicates the
+ * direction: IOREQ_READ means a read from <port> to <buffer> and
+ * IOREQ_WRITE means a write from <buffer> to <port>. Each access has
+ * width <size>.
+ */
+int hvmemul_do_pio_buffer(uint16_t port,
+ unsigned int size,
+ uint8_t dir,
+ void *buffer)
+{
+ unsigned long one_rep = 1;
+
+ return hvmemul_do_io_buffer(0, port, &one_rep, size, dir, 0, buffer);
+}
+
+/*
+ * Perform I/O between <port> and guest RAM starting at <ram_addr>.
+ * <dir> indicates the direction: IOREQ_READ means a read from <port> to
+ * RAM and IOREQ_WRITE means a write from RAM to <port>. Each access has
+ * width <size> and up to *<reps> accesses will be performed. If
+ * X86EMUL_OKAY is returned then <reps> will be updated with the number
+ * of accesses actually performed.
+ * Each access will be done to/from successive RAM addresses, increasing
+ * if <df> is 0 or decreasing if <df> is 1.
+ */
+static int hvmemul_do_pio_addr(uint16_t port,
+ unsigned long *reps,
+ unsigned int size,
+ uint8_t dir,
+ bool_t df,
+ paddr_t ram_addr)
+{
+ return hvmemul_do_io_addr(0, port, reps, size, dir, df, ram_addr);
+}
+
+/*
+ * Perform I/O between MMIO space starting at <mmio_gpa> and <buffer>.
+ * <dir> indicates the direction: IOREQ_READ means a read from MMIO to
+ * <buffer> and IOREQ_WRITE means a write from <buffer> to MMIO. Each
+ * access has width <size> and up to *<reps> accesses will be performed.
+ * If X86EMUL_OKAY is returned then <reps> will be updated with the number
+ * of accesses actually performed.
+ * Each access will be done to/from successive MMIO addresses, increasing
+ * if <df> is 0 or decreasing if <df> is 1.
+ *
+ * NOTE: If *<reps> is greater than 1, each access will use the
+ * <buffer> pointer; there is no implicit interation over a
+ * block of memory starting at <buffer>.
+ */
+static int hvmemul_do_mmio_buffer(paddr_t mmio_gpa,
+ unsigned long *reps,
+ unsigned int size,
+ uint8_t dir,
+ bool_t df,
+ void *buffer)
+{
+ return hvmemul_do_io_buffer(1, mmio_gpa, reps, size, dir, df, buffer);
+}
+
+/*
+ * Perform I/O between MMIO space starting at <mmio_gpa> and guest RAM
+ * starting at <ram_gpa>. <dir> indicates the direction: IOREQ_READ
+ * means a read from MMIO to RAM and IOREQ_WRITE means a write from RAM
+ * to MMIO. Each access has width <size> and up to *<reps> accesses will
+ * be performed. If X86EMUL_OKAY is returned then <reps> will be updated
+ * with the number of accesses actually performed.
+ * Each access will be done to/from successive RAM *and* MMIO addresses,
+ * increasing if <df> is 0 or decreasing if <df> is 1.
+ */
+static int hvmemul_do_mmio_addr(paddr_t mmio_gpa,
+ unsigned long *reps,
+ unsigned int size,
+ uint8_t dir,
+ bool_t df,
+ paddr_t ram_gpa)
{
- return hvmemul_do_io(1, gpa, reps, size, ram_gpa, dir, df, p_data);
+ return hvmemul_do_io_addr(1, mmio_gpa, reps, size, dir, df, ram_gpa);
}
/*
@@ -503,7 +587,8 @@ static int __hvmemul_read(
gpa = (((paddr_t)vio->mmio_gpfn << PAGE_SHIFT) | off);
while ( (off + chunk) <= PAGE_SIZE )
{
- rc = hvmemul_do_mmio(gpa, &reps, chunk, 0, IOREQ_READ, 0, p_data);
+ rc = hvmemul_do_mmio_buffer(gpa, &reps, chunk, IOREQ_READ, 0,
+ p_data);
if ( rc != X86EMUL_OKAY || bytes == chunk )
return rc;
addr += chunk;
@@ -537,7 +622,8 @@ static int __hvmemul_read(
hvmemul_ctxt);
while ( rc == X86EMUL_OKAY )
{
- rc = hvmemul_do_mmio(gpa, &reps, chunk, 0, IOREQ_READ, 0, p_data);
+ rc = hvmemul_do_mmio_buffer(gpa, &reps, chunk, IOREQ_READ, 0,
+ p_data);
if ( rc != X86EMUL_OKAY || bytes == chunk )
break;
addr += chunk;
@@ -645,7 +731,8 @@ static int hvmemul_write(
gpa = (((paddr_t)vio->mmio_gpfn << PAGE_SHIFT) | off);
while ( (off + chunk) <= PAGE_SIZE )
{
- rc = hvmemul_do_mmio(gpa, &reps, chunk, 0, IOREQ_WRITE, 0, p_data);
+ rc = hvmemul_do_mmio_buffer(gpa, &reps, chunk, IOREQ_WRITE, 0,
+ p_data);
if ( rc != X86EMUL_OKAY || bytes == chunk )
return rc;
addr += chunk;
@@ -675,7 +762,8 @@ static int hvmemul_write(
hvmemul_ctxt);
while ( rc == X86EMUL_OKAY )
{
- rc = hvmemul_do_mmio(gpa, &reps, chunk, 0, IOREQ_WRITE, 0, p_data);
+ rc = hvmemul_do_mmio_buffer(gpa, &reps, chunk, IOREQ_WRITE, 0,
+ p_data);
if ( rc != X86EMUL_OKAY || bytes == chunk )
break;
addr += chunk;
@@ -849,8 +937,8 @@ static int hvmemul_rep_ins(
if ( p2mt == p2m_mmio_direct || p2mt == p2m_mmio_dm )
return X86EMUL_UNHANDLEABLE;
- return hvmemul_do_pio(src_port, reps, bytes_per_rep, gpa, IOREQ_READ,
- !!(ctxt->regs->eflags & X86_EFLAGS_DF), NULL);
+ return hvmemul_do_pio_addr(src_port, reps, bytes_per_rep, IOREQ_READ,
+ !!(ctxt->regs->eflags & X86_EFLAGS_DF), gpa);
}
static int hvmemul_rep_outs(
@@ -887,8 +975,8 @@ static int hvmemul_rep_outs(
if ( p2mt == p2m_mmio_direct || p2mt == p2m_mmio_dm )
return X86EMUL_UNHANDLEABLE;
- return hvmemul_do_pio(dst_port, reps, bytes_per_rep, gpa, IOREQ_WRITE,
- !!(ctxt->regs->eflags & X86_EFLAGS_DF), NULL);
+ return hvmemul_do_pio_addr(dst_port, reps, bytes_per_rep, IOREQ_WRITE,
+ !!(ctxt->regs->eflags & X86_EFLAGS_DF), gpa);
}
static int hvmemul_rep_movs(
@@ -944,12 +1032,12 @@ static int hvmemul_rep_movs(
return X86EMUL_UNHANDLEABLE;
if ( sp2mt == p2m_mmio_dm )
- return hvmemul_do_mmio(
- sgpa, reps, bytes_per_rep, dgpa, IOREQ_READ, df, NULL);
+ return hvmemul_do_mmio_addr(
+ sgpa, reps, bytes_per_rep, IOREQ_READ, df, dgpa);
if ( dp2mt == p2m_mmio_dm )
- return hvmemul_do_mmio(
- dgpa, reps, bytes_per_rep, sgpa, IOREQ_WRITE, df, NULL);
+ return hvmemul_do_mmio_addr(
+ dgpa, reps, bytes_per_rep, IOREQ_WRITE, df, sgpa);
/* RAM-to-RAM copy: emulate as equivalent of memmove(dgpa, sgpa, bytes). */
bytes = *reps * bytes_per_rep;
@@ -1102,8 +1190,8 @@ static int hvmemul_rep_stos(
return X86EMUL_UNHANDLEABLE;
case p2m_mmio_dm:
- return hvmemul_do_mmio(gpa, reps, bytes_per_rep, 0, IOREQ_WRITE, df,
- p_data);
+ return hvmemul_do_mmio_buffer(gpa, reps, bytes_per_rep, IOREQ_WRITE,
df,
+ p_data);
}
}
@@ -1140,9 +1228,8 @@ static int hvmemul_read_io(
unsigned long *val,
struct x86_emulate_ctxt *ctxt)
{
- unsigned long reps = 1;
*val = 0;
- return hvmemul_do_pio(port, &reps, bytes, 0, IOREQ_READ, 0, val);
+ return hvmemul_do_pio_buffer(port, bytes, IOREQ_READ, val);
}
static int hvmemul_write_io(
@@ -1151,8 +1238,7 @@ static int hvmemul_write_io(
unsigned long val,
struct x86_emulate_ctxt *ctxt)
{
- unsigned long reps = 1;
- return hvmemul_do_pio(port, &reps, bytes, 0, IOREQ_WRITE, 0, &val);
+ return hvmemul_do_pio_buffer(port, bytes, IOREQ_WRITE, &val);
}
static int hvmemul_read_cr(
diff --git a/xen/arch/x86/hvm/io.c b/xen/arch/x86/hvm/io.c
index 68fb890..c0964ec 100644
--- a/xen/arch/x86/hvm/io.c
+++ b/xen/arch/x86/hvm/io.c
@@ -132,7 +132,7 @@ int handle_pio(uint16_t port, unsigned int size, int dir)
{
struct vcpu *curr = current;
struct hvm_vcpu_io *vio = &curr->arch.hvm_vcpu.hvm_io;
- unsigned long data, reps = 1;
+ unsigned long data;
int rc;
ASSERT((size - 1) < 4 && size != 3);
@@ -140,7 +140,7 @@ int handle_pio(uint16_t port, unsigned int size, int dir)
if ( dir == IOREQ_WRITE )
data = guest_cpu_user_regs()->eax;
- rc = hvmemul_do_pio(port, &reps, size, 0, dir, 0, &data);
+ rc = hvmemul_do_pio_buffer(port, size, dir, &data);
switch ( rc )
{
diff --git a/xen/include/asm-x86/hvm/emulate.h
b/xen/include/asm-x86/hvm/emulate.h
index b3971c8..594be38 100644
--- a/xen/include/asm-x86/hvm/emulate.h
+++ b/xen/include/asm-x86/hvm/emulate.h
@@ -50,11 +50,22 @@ struct segment_register *hvmemul_get_seg_reg(
enum x86_segment seg,
struct hvm_emulate_ctxt *hvmemul_ctxt);
-int hvmemul_do_pio(
- unsigned long port, unsigned long *reps, int size,
- paddr_t ram_gpa, int dir, int df, void *p_data);
+int hvmemul_do_pio_buffer(uint16_t port,
+ unsigned int size,
+ uint8_t dir,
+ void *buffer);
void hvm_dump_emulation_state(const char *prefix,
struct hvm_emulate_ctxt *hvmemul_ctxt);
#endif /* __ASM_X86_HVM_EMULATE_H__ */
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
--
1.7.10.4
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