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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-changelog] [xen master] x86/HVM: emulate with no writes
commit 4ae69fc45c815c32ae0fd6edb2bc159fd9d8a559
Author: Razvan Cojocaru <rcojocaru@xxxxxxxxxxxxxxx>
AuthorDate: Thu Sep 18 14:53:52 2014 +0200
Commit: Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Thu Sep 18 14:53:52 2014 +0200
x86/HVM: emulate with no writes
Added support for emulating an instruction with no memory writes.
Additionally, introduced hvm_emulate_one_full(), which inspects
possible return values from the hvm_emulate_one() functions
(EXCEPTION, UNHANDLEABLE) and acts on them.
Signed-off-by: Razvan Cojocaru <rcojocaru@xxxxxxxxxxxxxxx>
Acked-by: Jan Beulich <jbeulich@xxxxxxxx>
---
xen/arch/x86/hvm/emulate.c | 175 ++++++++++++++++++++++++++++++++++++-
xen/include/asm-x86/hvm/emulate.h | 5 +
2 files changed, 177 insertions(+), 3 deletions(-)
diff --git a/xen/arch/x86/hvm/emulate.c b/xen/arch/x86/hvm/emulate.c
index 86cf432..6ab06e0 100644
--- a/xen/arch/x86/hvm/emulate.c
+++ b/xen/arch/x86/hvm/emulate.c
@@ -690,6 +690,94 @@ static int hvmemul_write(
return X86EMUL_OKAY;
}
+static int hvmemul_write_discard(
+ enum x86_segment seg,
+ unsigned long offset,
+ void *p_data,
+ unsigned int bytes,
+ struct x86_emulate_ctxt *ctxt)
+{
+ /* Discarding the write. */
+ return X86EMUL_OKAY;
+}
+
+static int hvmemul_rep_ins_discard(
+ uint16_t src_port,
+ enum x86_segment dst_seg,
+ unsigned long dst_offset,
+ unsigned int bytes_per_rep,
+ unsigned long *reps,
+ struct x86_emulate_ctxt *ctxt)
+{
+ return X86EMUL_OKAY;
+}
+
+static int hvmemul_rep_movs_discard(
+ enum x86_segment src_seg,
+ unsigned long src_offset,
+ enum x86_segment dst_seg,
+ unsigned long dst_offset,
+ unsigned int bytes_per_rep,
+ unsigned long *reps,
+ struct x86_emulate_ctxt *ctxt)
+{
+ return X86EMUL_OKAY;
+}
+
+static int hvmemul_rep_outs_discard(
+ enum x86_segment src_seg,
+ unsigned long src_offset,
+ uint16_t dst_port,
+ unsigned int bytes_per_rep,
+ unsigned long *reps,
+ struct x86_emulate_ctxt *ctxt)
+{
+ return X86EMUL_OKAY;
+}
+
+static int hvmemul_cmpxchg_discard(
+ enum x86_segment seg,
+ unsigned long offset,
+ void *p_old,
+ void *p_new,
+ unsigned int bytes,
+ struct x86_emulate_ctxt *ctxt)
+{
+ return X86EMUL_OKAY;
+}
+
+static int hvmemul_read_io_discard(
+ unsigned int port,
+ unsigned int bytes,
+ unsigned long *val,
+ struct x86_emulate_ctxt *ctxt)
+{
+ return X86EMUL_OKAY;
+}
+
+static int hvmemul_write_io_discard(
+ unsigned int port,
+ unsigned int bytes,
+ unsigned long val,
+ struct x86_emulate_ctxt *ctxt)
+{
+ return X86EMUL_OKAY;
+}
+
+static int hvmemul_write_msr_discard(
+ unsigned long reg,
+ uint64_t val,
+ struct x86_emulate_ctxt *ctxt)
+{
+ return X86EMUL_OKAY;
+}
+
+static int hvmemul_wbinvd_discard(
+ struct x86_emulate_ctxt *ctxt)
+{
+ return X86EMUL_OKAY;
+}
+
static int hvmemul_cmpxchg(
enum x86_segment seg,
unsigned long offset,
@@ -1140,8 +1228,33 @@ static const struct x86_emulate_ops hvm_emulate_ops = {
.invlpg = hvmemul_invlpg
};
-int hvm_emulate_one(
- struct hvm_emulate_ctxt *hvmemul_ctxt)
+static const struct x86_emulate_ops hvm_emulate_ops_no_write = {
+ .read = hvmemul_read,
+ .insn_fetch = hvmemul_insn_fetch,
+ .write = hvmemul_write_discard,
+ .cmpxchg = hvmemul_cmpxchg_discard,
+ .rep_ins = hvmemul_rep_ins_discard,
+ .rep_outs = hvmemul_rep_outs_discard,
+ .rep_movs = hvmemul_rep_movs_discard,
+ .read_segment = hvmemul_read_segment,
+ .write_segment = hvmemul_write_segment,
+ .read_io = hvmemul_read_io_discard,
+ .write_io = hvmemul_write_io_discard,
+ .read_cr = hvmemul_read_cr,
+ .write_cr = hvmemul_write_cr,
+ .read_msr = hvmemul_read_msr,
+ .write_msr = hvmemul_write_msr_discard,
+ .wbinvd = hvmemul_wbinvd_discard,
+ .cpuid = hvmemul_cpuid,
+ .inject_hw_exception = hvmemul_inject_hw_exception,
+ .inject_sw_interrupt = hvmemul_inject_sw_interrupt,
+ .get_fpu = hvmemul_get_fpu,
+ .put_fpu = hvmemul_put_fpu,
+ .invlpg = hvmemul_invlpg
+};
+
+static int _hvm_emulate_one(struct hvm_emulate_ctxt *hvmemul_ctxt,
+ const struct x86_emulate_ops *ops)
{
struct cpu_user_regs *regs = hvmemul_ctxt->ctxt.regs;
struct vcpu *curr = current;
@@ -1193,7 +1306,7 @@ int hvm_emulate_one(
vio->mmio_retrying = vio->mmio_retry;
vio->mmio_retry = 0;
- rc = x86_emulate(&hvmemul_ctxt->ctxt, &hvm_emulate_ops);
+ rc = x86_emulate(&hvmemul_ctxt->ctxt, ops);
if ( rc == X86EMUL_OKAY && vio->mmio_retry )
rc = X86EMUL_RETRY;
@@ -1241,6 +1354,62 @@ int hvm_emulate_one(
return X86EMUL_OKAY;
}
+int hvm_emulate_one(
+ struct hvm_emulate_ctxt *hvmemul_ctxt)
+{
+ return _hvm_emulate_one(hvmemul_ctxt, &hvm_emulate_ops);
+}
+
+int hvm_emulate_one_no_write(
+ struct hvm_emulate_ctxt *hvmemul_ctxt)
+{
+ return _hvm_emulate_one(hvmemul_ctxt, &hvm_emulate_ops_no_write);
+}
+
+void hvm_mem_event_emulate_one(bool_t nowrite, unsigned int trapnr,
+ unsigned int errcode)
+{
+ struct hvm_emulate_ctxt ctx = {{ 0 }};
+ int rc;
+
+ hvm_emulate_prepare(&ctx, guest_cpu_user_regs());
+
+ if ( nowrite )
+ rc = hvm_emulate_one_no_write(&ctx);
+ else
+ rc = hvm_emulate_one(&ctx);
+
+ switch ( rc )
+ {
+ case X86EMUL_RETRY:
+ /*
+ * This function is called when handling an EPT-related mem_event
+ * reply. As such, nothing else needs to be done here, since simply
+ * returning makes the current instruction cause a page fault again,
+ * consistent with X86EMUL_RETRY.
+ */
+ return;
+ case X86EMUL_UNHANDLEABLE:
+ gdprintk(XENLOG_DEBUG, "Emulation failed @ %04x:%lx: "
+ "%02x %02x %02x %02x %02x %02x %02x %02x %02x %02x\n",
+ hvmemul_get_seg_reg(x86_seg_cs, &ctx)->sel,
+ ctx.insn_buf_eip,
+ ctx.insn_buf[0], ctx.insn_buf[1],
+ ctx.insn_buf[2], ctx.insn_buf[3],
+ ctx.insn_buf[4], ctx.insn_buf[5],
+ ctx.insn_buf[6], ctx.insn_buf[7],
+ ctx.insn_buf[8], ctx.insn_buf[9]);
+ hvm_inject_hw_exception(trapnr, errcode);
+ break;
+ case X86EMUL_EXCEPTION:
+ if ( ctx.exn_pending )
+ hvm_inject_hw_exception(ctx.exn_vector, ctx.exn_error_code);
+ break;
+ }
+
+ hvm_emulate_writeback(&ctx);
+}
+
void hvm_emulate_prepare(
struct hvm_emulate_ctxt *hvmemul_ctxt,
struct cpu_user_regs *regs)
diff --git a/xen/include/asm-x86/hvm/emulate.h
b/xen/include/asm-x86/hvm/emulate.h
index 00a06cc..efff97e 100644
--- a/xen/include/asm-x86/hvm/emulate.h
+++ b/xen/include/asm-x86/hvm/emulate.h
@@ -37,6 +37,11 @@ struct hvm_emulate_ctxt {
int hvm_emulate_one(
struct hvm_emulate_ctxt *hvmemul_ctxt);
+int hvm_emulate_one_no_write(
+ struct hvm_emulate_ctxt *hvmemul_ctxt);
+void hvm_mem_event_emulate_one(bool_t nowrite,
+ unsigned int trapnr,
+ unsigned int errcode);
void hvm_emulate_prepare(
struct hvm_emulate_ctxt *hvmemul_ctxt,
struct cpu_user_regs *regs);
--
generated by git-patchbot for /home/xen/git/xen.git#master
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