[Xen-devel] [PATCH 01/15] x86/hvm: Rename hvm_emulate_init() and hvm_emulate_prepare() for clarity

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

 * Move hvm_emulate_init() to immediately hvm_emulate_prepare(), as they are
   very closely related.
 * Rename hvm_emulate_prepare() to hvm_emulate_init_once() and
   hvm_emulate_init() to hvm_emulate_init_per_insn() to make it clearer how to
   and when to use them.

No functional change.

Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
CC: Jan Beulich <JBeulich@xxxxxxxx>
CC: Paul Durrant <paul.durrant@xxxxxxxxxx>
CC: Jun Nakajima <jun.nakajima@xxxxxxxxx>
CC: Kevin Tian <kevin.tian@xxxxxxxxx>
CC: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
CC: Suravee Suthikulpanit <suravee.suthikulpanit@xxxxxxx>
CC: Wei Liu <wei.liu2@xxxxxxxxxx>

As hvm_emulate_prepare() was new in 4.8, it would be a good idea to take this
patch to avoid future confusion on the stable-4.8 branch
---
 xen/arch/x86/hvm/emulate.c        | 111 +++++++++++++++++++-------------------
 xen/arch/x86/hvm/hvm.c            |   2 +-
 xen/arch/x86/hvm/io.c             |   2 +-
 xen/arch/x86/hvm/ioreq.c          |   2 +-
 xen/arch/x86/hvm/svm/emulate.c    |   4 +-
 xen/arch/x86/hvm/vmx/realmode.c   |   2 +-
 xen/include/asm-x86/hvm/emulate.h |   6 ++-
 7 files changed, 66 insertions(+), 63 deletions(-)

diff --git a/xen/arch/x86/hvm/emulate.c b/xen/arch/x86/hvm/emulate.c
index e9b8f8c..3ab0e8e 100644
--- a/xen/arch/x86/hvm/emulate.c
+++ b/xen/arch/x86/hvm/emulate.c
@@ -1755,57 +1755,6 @@ static const struct x86_emulate_ops 
hvm_emulate_ops_no_write = {
     .vmfunc        = hvmemul_vmfunc,
 };
 
-void hvm_emulate_init(
-    struct hvm_emulate_ctxt *hvmemul_ctxt,
-    const unsigned char *insn_buf,
-    unsigned int insn_bytes)
-{
-    struct vcpu *curr = current;
-    unsigned int pfec = PFEC_page_present;
-    unsigned long addr;
-
-    if ( hvm_long_mode_enabled(curr) &&
-         hvmemul_ctxt->seg_reg[x86_seg_cs].attr.fields.l )
-    {
-        hvmemul_ctxt->ctxt.addr_size = hvmemul_ctxt->ctxt.sp_size = 64;
-    }
-    else
-    {
-        hvmemul_ctxt->ctxt.addr_size =
-            hvmemul_ctxt->seg_reg[x86_seg_cs].attr.fields.db ? 32 : 16;
-        hvmemul_ctxt->ctxt.sp_size =
-            hvmemul_ctxt->seg_reg[x86_seg_ss].attr.fields.db ? 32 : 16;
-    }
-
-    if ( hvmemul_ctxt->seg_reg[x86_seg_ss].attr.fields.dpl == 3 )
-        pfec |= PFEC_user_mode;
-
-    hvmemul_ctxt->insn_buf_eip = hvmemul_ctxt->ctxt.regs->eip;
-    if ( !insn_bytes )
-    {
-        hvmemul_ctxt->insn_buf_bytes =
-            hvm_get_insn_bytes(curr, hvmemul_ctxt->insn_buf) ?:
-            (hvm_virtual_to_linear_addr(x86_seg_cs,
-                                        &hvmemul_ctxt->seg_reg[x86_seg_cs],
-                                        hvmemul_ctxt->insn_buf_eip,
-                                        sizeof(hvmemul_ctxt->insn_buf),
-                                        hvm_access_insn_fetch,
-                                        hvmemul_ctxt->ctxt.addr_size,
-                                        &addr) &&
-             hvm_fetch_from_guest_virt_nofault(hvmemul_ctxt->insn_buf, addr,
-                                               sizeof(hvmemul_ctxt->insn_buf),
-                                               pfec) == HVMCOPY_okay) ?
-            sizeof(hvmemul_ctxt->insn_buf) : 0;
-    }
-    else
-    {
-        hvmemul_ctxt->insn_buf_bytes = insn_bytes;
-        memcpy(hvmemul_ctxt->insn_buf, insn_buf, insn_bytes);
-    }
-
-    hvmemul_ctxt->exn_pending = 0;
-}
-
 static int _hvm_emulate_one(struct hvm_emulate_ctxt *hvmemul_ctxt,
     const struct x86_emulate_ops *ops)
 {
@@ -1815,7 +1764,8 @@ static int _hvm_emulate_one(struct hvm_emulate_ctxt 
*hvmemul_ctxt,
     struct hvm_vcpu_io *vio = &curr->arch.hvm_vcpu.hvm_io;
     int rc;
 
-    hvm_emulate_init(hvmemul_ctxt, vio->mmio_insn, vio->mmio_insn_bytes);
+    hvm_emulate_init_per_insn(hvmemul_ctxt, vio->mmio_insn,
+                              vio->mmio_insn_bytes);
 
     vio->mmio_retry = 0;
 
@@ -1915,7 +1865,7 @@ int hvm_emulate_one_mmio(unsigned long mfn, unsigned long 
gla)
     else
         ops = &hvm_ro_emulate_ops_mmio;
 
-    hvm_emulate_prepare(&ctxt, guest_cpu_user_regs());
+    hvm_emulate_init_once(&ctxt, guest_cpu_user_regs());
     ctxt.ctxt.data = &mmio_ro_ctxt;
     rc = _hvm_emulate_one(&ctxt, ops);
     switch ( rc )
@@ -1940,7 +1890,7 @@ void hvm_emulate_one_vm_event(enum emul_kind kind, 
unsigned int trapnr,
     struct hvm_emulate_ctxt ctx = {{ 0 }};
     int rc;
 
-    hvm_emulate_prepare(&ctx, guest_cpu_user_regs());
+    hvm_emulate_init_once(&ctx, guest_cpu_user_regs());
 
     switch ( kind )
     {
@@ -1992,7 +1942,7 @@ void hvm_emulate_one_vm_event(enum emul_kind kind, 
unsigned int trapnr,
     hvm_emulate_writeback(&ctx);
 }
 
-void hvm_emulate_prepare(
+void hvm_emulate_init_once(
     struct hvm_emulate_ctxt *hvmemul_ctxt,
     struct cpu_user_regs *regs)
 {
@@ -2006,6 +1956,57 @@ void hvm_emulate_prepare(
     hvmemul_get_seg_reg(x86_seg_ss, hvmemul_ctxt);
 }
 
+void hvm_emulate_init_per_insn(
+    struct hvm_emulate_ctxt *hvmemul_ctxt,
+    const unsigned char *insn_buf,
+    unsigned int insn_bytes)
+{
+    struct vcpu *curr = current;
+    unsigned int pfec = PFEC_page_present;
+    unsigned long addr;
+
+    if ( hvm_long_mode_enabled(curr) &&
+         hvmemul_ctxt->seg_reg[x86_seg_cs].attr.fields.l )
+    {
+        hvmemul_ctxt->ctxt.addr_size = hvmemul_ctxt->ctxt.sp_size = 64;
+    }
+    else
+    {
+        hvmemul_ctxt->ctxt.addr_size =
+            hvmemul_ctxt->seg_reg[x86_seg_cs].attr.fields.db ? 32 : 16;
+        hvmemul_ctxt->ctxt.sp_size =
+            hvmemul_ctxt->seg_reg[x86_seg_ss].attr.fields.db ? 32 : 16;
+    }
+
+    if ( hvmemul_ctxt->seg_reg[x86_seg_ss].attr.fields.dpl == 3 )
+        pfec |= PFEC_user_mode;
+
+    hvmemul_ctxt->insn_buf_eip = hvmemul_ctxt->ctxt.regs->eip;
+    if ( !insn_bytes )
+    {
+        hvmemul_ctxt->insn_buf_bytes =
+            hvm_get_insn_bytes(curr, hvmemul_ctxt->insn_buf) ?:
+            (hvm_virtual_to_linear_addr(x86_seg_cs,
+                                        &hvmemul_ctxt->seg_reg[x86_seg_cs],
+                                        hvmemul_ctxt->insn_buf_eip,
+                                        sizeof(hvmemul_ctxt->insn_buf),
+                                        hvm_access_insn_fetch,
+                                        hvmemul_ctxt->ctxt.addr_size,
+                                        &addr) &&
+             hvm_fetch_from_guest_virt_nofault(hvmemul_ctxt->insn_buf, addr,
+                                               sizeof(hvmemul_ctxt->insn_buf),
+                                               pfec) == HVMCOPY_okay) ?
+            sizeof(hvmemul_ctxt->insn_buf) : 0;
+    }
+    else
+    {
+        hvmemul_ctxt->insn_buf_bytes = insn_bytes;
+        memcpy(hvmemul_ctxt->insn_buf, insn_buf, insn_bytes);
+    }
+
+    hvmemul_ctxt->exn_pending = 0;
+}
+
 void hvm_emulate_writeback(
     struct hvm_emulate_ctxt *hvmemul_ctxt)
 {
diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index f76dd90..25dc759 100644
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -4058,7 +4058,7 @@ void hvm_ud_intercept(struct cpu_user_regs *regs)
 {
     struct hvm_emulate_ctxt ctxt;
 
-    hvm_emulate_prepare(&ctxt, regs);
+    hvm_emulate_init_once(&ctxt, regs);
 
     if ( opt_hvm_fep )
     {
diff --git a/xen/arch/x86/hvm/io.c b/xen/arch/x86/hvm/io.c
index 1e7a5f9..7305801 100644
--- a/xen/arch/x86/hvm/io.c
+++ b/xen/arch/x86/hvm/io.c
@@ -87,7 +87,7 @@ int handle_mmio(void)
 
     ASSERT(!is_pvh_vcpu(curr));
 
-    hvm_emulate_prepare(&ctxt, guest_cpu_user_regs());
+    hvm_emulate_init_once(&ctxt, guest_cpu_user_regs());
 
     rc = hvm_emulate_one(&ctxt);
 
diff --git a/xen/arch/x86/hvm/ioreq.c b/xen/arch/x86/hvm/ioreq.c
index d2245e2..88071ab 100644
--- a/xen/arch/x86/hvm/ioreq.c
+++ b/xen/arch/x86/hvm/ioreq.c
@@ -167,7 +167,7 @@ bool_t handle_hvm_io_completion(struct vcpu *v)
     {
         struct hvm_emulate_ctxt ctxt;
 
-        hvm_emulate_prepare(&ctxt, guest_cpu_user_regs());
+        hvm_emulate_init_once(&ctxt, guest_cpu_user_regs());
         vmx_realmode_emulate_one(&ctxt);
         hvm_emulate_writeback(&ctxt);
 
diff --git a/xen/arch/x86/hvm/svm/emulate.c b/xen/arch/x86/hvm/svm/emulate.c
index a5545ea..9cdbe9e 100644
--- a/xen/arch/x86/hvm/svm/emulate.c
+++ b/xen/arch/x86/hvm/svm/emulate.c
@@ -107,8 +107,8 @@ int __get_instruction_length_from_list(struct vcpu *v,
 #endif
 
     ASSERT(v == current);
-    hvm_emulate_prepare(&ctxt, guest_cpu_user_regs());
-    hvm_emulate_init(&ctxt, NULL, 0);
+    hvm_emulate_init_once(&ctxt, guest_cpu_user_regs());
+    hvm_emulate_init_per_insn(&ctxt, NULL, 0);
     state = x86_decode_insn(&ctxt.ctxt, hvmemul_insn_fetch);
     if ( IS_ERR_OR_NULL(state) )
         return 0;
diff --git a/xen/arch/x86/hvm/vmx/realmode.c b/xen/arch/x86/hvm/vmx/realmode.c
index e83a61f..9002638 100644
--- a/xen/arch/x86/hvm/vmx/realmode.c
+++ b/xen/arch/x86/hvm/vmx/realmode.c
@@ -179,7 +179,7 @@ void vmx_realmode(struct cpu_user_regs *regs)
     if ( intr_info & INTR_INFO_VALID_MASK )
         __vmwrite(VM_ENTRY_INTR_INFO, 0);
 
-    hvm_emulate_prepare(&hvmemul_ctxt, regs);
+    hvm_emulate_init_once(&hvmemul_ctxt, regs);
 
     /* Only deliver interrupts into emulated real mode. */
     if ( !(curr->arch.hvm_vcpu.guest_cr[0] & X86_CR0_PE) &&
diff --git a/xen/include/asm-x86/hvm/emulate.h 
b/xen/include/asm-x86/hvm/emulate.h
index f610673..d4186a2 100644
--- a/xen/include/asm-x86/hvm/emulate.h
+++ b/xen/include/asm-x86/hvm/emulate.h
@@ -51,10 +51,12 @@ int hvm_emulate_one_no_write(
 void hvm_emulate_one_vm_event(enum emul_kind kind,
     unsigned int trapnr,
     unsigned int errcode);
-void hvm_emulate_prepare(
+/* Must be called once to set up hvmemul state. */
+void hvm_emulate_init_once(
     struct hvm_emulate_ctxt *hvmemul_ctxt,
     struct cpu_user_regs *regs);
-void hvm_emulate_init(
+/* Must be called once before each instruction emulated. */
+void hvm_emulate_init_per_insn(
     struct hvm_emulate_ctxt *hvmemul_ctxt,
     const unsigned char *insn_buf,
     unsigned int insn_bytes);
-- 
2.1.4


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