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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH 02/15] x86/emul: Simplfy emulation state setup
The current code to set up emulation state is ad-hoc and error prone.
* Consistently zero all emulation state structures.
* Avoid explicitly initialising some state to 0.
* Explicitly identify all input and output state in x86_emulate_ctxt. This
involves rearanging some fields.
* Have x86_decode() explicitly initalise all output state at its start.
In addition, move the calculation of hvmemul_ctxt->ctxt.swint_emulate from
_hvm_emulate_one() to hvm_emulate_init_once(), as it doesn't need
recalculating for each instruction.
Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
CC: Jan Beulich <JBeulich@xxxxxxxx>
CC: Tim Deegan <tim@xxxxxxx>
CC: George Dunlap <george.dunlap@xxxxxxxxxxxxx>
CC: Paul Durrant <paul.durrant@xxxxxxxxxx>
---
xen/arch/x86/hvm/emulate.c | 28 +++++++++++++++-------------
xen/arch/x86/mm.c | 3 ++-
xen/arch/x86/mm/shadow/common.c | 4 ++--
xen/arch/x86/x86_emulate/x86_emulate.c | 2 ++
xen/arch/x86/x86_emulate/x86_emulate.h | 22 +++++++++++++++-------
5 files changed, 36 insertions(+), 23 deletions(-)
diff --git a/xen/arch/x86/hvm/emulate.c b/xen/arch/x86/hvm/emulate.c
index 3ab0e8e..f24e211 100644
--- a/xen/arch/x86/hvm/emulate.c
+++ b/xen/arch/x86/hvm/emulate.c
@@ -1769,13 +1769,6 @@ static int _hvm_emulate_one(struct hvm_emulate_ctxt
*hvmemul_ctxt,
vio->mmio_retry = 0;
- if ( cpu_has_vmx )
- hvmemul_ctxt->ctxt.swint_emulate = x86_swint_emulate_none;
- else if ( cpu_has_svm_nrips )
- hvmemul_ctxt->ctxt.swint_emulate = x86_swint_emulate_icebp;
- else
- hvmemul_ctxt->ctxt.swint_emulate = x86_swint_emulate_all;
-
rc = x86_emulate(&hvmemul_ctxt->ctxt, ops);
if ( rc == X86EMUL_OKAY && vio->mmio_retry )
@@ -1946,14 +1939,23 @@ void hvm_emulate_init_once(
struct hvm_emulate_ctxt *hvmemul_ctxt,
struct cpu_user_regs *regs)
{
- hvmemul_ctxt->intr_shadow = hvm_funcs.get_interrupt_shadow(current);
- hvmemul_ctxt->ctxt.regs = regs;
- hvmemul_ctxt->ctxt.force_writeback = 1;
- hvmemul_ctxt->seg_reg_accessed = 0;
- hvmemul_ctxt->seg_reg_dirty = 0;
- hvmemul_ctxt->set_context = 0;
+ struct vcpu *curr = current;
+
+ memset(hvmemul_ctxt, 0, sizeof(*hvmemul_ctxt));
+
+ hvmemul_ctxt->intr_shadow = hvm_funcs.get_interrupt_shadow(curr);
hvmemul_get_seg_reg(x86_seg_cs, hvmemul_ctxt);
hvmemul_get_seg_reg(x86_seg_ss, hvmemul_ctxt);
+
+ hvmemul_ctxt->ctxt.regs = regs;
+ hvmemul_ctxt->ctxt.force_writeback = true;
+
+ if ( cpu_has_vmx )
+ hvmemul_ctxt->ctxt.swint_emulate = x86_swint_emulate_none;
+ else if ( cpu_has_svm_nrips )
+ hvmemul_ctxt->ctxt.swint_emulate = x86_swint_emulate_icebp;
+ else
+ hvmemul_ctxt->ctxt.swint_emulate = x86_swint_emulate_all;
}
void hvm_emulate_init_per_insn(
diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index 03dcd71..9901f6f 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -5363,8 +5363,9 @@ int ptwr_do_page_fault(struct vcpu *v, unsigned long addr,
goto bail;
}
+ memset(&ptwr_ctxt, 0, sizeof(ptwr_ctxt));
+
ptwr_ctxt.ctxt.regs = regs;
- ptwr_ctxt.ctxt.force_writeback = 0;
ptwr_ctxt.ctxt.addr_size = ptwr_ctxt.ctxt.sp_size =
is_pv_32bit_domain(d) ? 32 : BITS_PER_LONG;
ptwr_ctxt.ctxt.swint_emulate = x86_swint_emulate_none;
diff --git a/xen/arch/x86/mm/shadow/common.c b/xen/arch/x86/mm/shadow/common.c
index ced2313..6f6668d 100644
--- a/xen/arch/x86/mm/shadow/common.c
+++ b/xen/arch/x86/mm/shadow/common.c
@@ -385,8 +385,9 @@ const struct x86_emulate_ops *shadow_init_emulation(
struct vcpu *v = current;
unsigned long addr;
+ memset(sh_ctxt, 0, sizeof(*sh_ctxt));
+
sh_ctxt->ctxt.regs = regs;
- sh_ctxt->ctxt.force_writeback = 0;
sh_ctxt->ctxt.swint_emulate = x86_swint_emulate_none;
if ( is_pv_vcpu(v) )
@@ -396,7 +397,6 @@ const struct x86_emulate_ops *shadow_init_emulation(
}
/* Segment cache initialisation. Primed with CS. */
- sh_ctxt->valid_seg_regs = 0;
creg = hvm_get_seg_reg(x86_seg_cs, sh_ctxt);
/* Work out the emulation mode. */
diff --git a/xen/arch/x86/x86_emulate/x86_emulate.c
b/xen/arch/x86/x86_emulate/x86_emulate.c
index 04f0dac..c5d9664 100644
--- a/xen/arch/x86/x86_emulate/x86_emulate.c
+++ b/xen/arch/x86/x86_emulate/x86_emulate.c
@@ -1904,6 +1904,8 @@ x86_decode(
state->regs = ctxt->regs;
state->eip = ctxt->regs->eip;
+ /* Initialise output state in x86_emulate_ctxt */
+ ctxt->opcode = ~0u;
ctxt->retire.byte = 0;
op_bytes = def_op_bytes = ad_bytes = def_ad_bytes = ctxt->addr_size/8;
diff --git a/xen/arch/x86/x86_emulate/x86_emulate.h
b/xen/arch/x86/x86_emulate/x86_emulate.h
index 993c576..93b268e 100644
--- a/xen/arch/x86/x86_emulate/x86_emulate.h
+++ b/xen/arch/x86/x86_emulate/x86_emulate.h
@@ -412,6 +412,10 @@ struct cpu_user_regs;
struct x86_emulate_ctxt
{
+ /*
+ * Input state:
+ */
+
/* Register state before/after emulation. */
struct cpu_user_regs *regs;
@@ -421,14 +425,21 @@ struct x86_emulate_ctxt
/* Stack pointer width in bits (16, 32 or 64). */
unsigned int sp_size;
- /* Canonical opcode (see below). */
- unsigned int opcode;
-
/* Software event injection support. */
enum x86_swint_emulation swint_emulate;
/* Set this if writes may have side effects. */
- uint8_t force_writeback;
+ bool force_writeback;
+
+ /* Caller data that can be used by x86_emulate_ops' routines. */
+ void *data;
+
+ /*
+ * Output state:
+ */
+
+ /* Canonical opcode (see below). */
+ unsigned int opcode;
/* Retirement state, set by the emulator (valid only on X86EMUL_OKAY). */
union {
@@ -439,9 +450,6 @@ struct x86_emulate_ctxt
} flags;
uint8_t byte;
} retire;
-
- /* Caller data that can be used by x86_emulate_ops' routines. */
- void *data;
};
/*
--
2.1.4
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