KVM: Allow passing 64-bit values to the emulated read/write API

This simplifies the API somewhat (by eliminating the special-case
cmpxchg8b on i386).

Signed-off-by: Avi Kivity <avi@qumranet.com>

3 files changed, 24 insertions, 99 deletions

diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index 911c8175cc08..67554034d001 100644
--- a/drivers/kvm/kvm_main.c
+++ b/drivers/kvm/kvm_main.c
@@ -970,7 +970,7 @@ void mark_page_dirty(struct kvm *kvm, gfn_t gfn)
 }
 
 static int emulator_read_std(unsigned long addr,
-                             unsigned long *val,
+                             void *val,
                              unsigned int bytes,
                              struct x86_emulate_ctxt *ctxt)
 {
@@ -1006,7 +1006,7 @@ static int emulator_read_std(unsigned long addr,
 }
 
 static int emulator_write_std(unsigned long addr,
-                              unsigned long val,
+                              const void *val,
                               unsigned int bytes,
                               struct x86_emulate_ctxt *ctxt)
 {
@@ -1016,7 +1016,7 @@ static int emulator_write_std(unsigned long addr,
 }
 
 static int emulator_read_emulated(unsigned long addr,
-                                  unsigned long *val,
+                                  void *val,
                                   unsigned int bytes,
                                   struct x86_emulate_ctxt *ctxt)
 {
@@ -1044,7 +1044,7 @@ static int emulator_read_emulated(unsigned long addr,
 }
 
 static int emulator_write_phys(struct kvm_vcpu *vcpu, gpa_t gpa,
-                               unsigned long val, int bytes)
+                               const void *val, int bytes)
 {
         struct page *page;
         void *virt;
@@ -1057,14 +1057,14 @@ static int emulator_write_phys(struct kvm_vcpu *vcpu, gpa_t gpa,
         kvm_mmu_pre_write(vcpu, gpa, bytes);
         mark_page_dirty(vcpu->kvm, gpa >> PAGE_SHIFT);
         virt = kmap_atomic(page, KM_USER0);
-        memcpy(virt + offset_in_page(gpa), &val, bytes);
+        memcpy(virt + offset_in_page(gpa), val, bytes);
         kunmap_atomic(virt, KM_USER0);
         kvm_mmu_post_write(vcpu, gpa, bytes);
         return 1;
 }
 
 static int emulator_write_emulated(unsigned long addr,
-                                   unsigned long val,
+                                   const void *val,
                                    unsigned int bytes,
                                    struct x86_emulate_ctxt *ctxt)
 {
@@ -1083,14 +1083,14 @@ static int emulator_write_emulated(unsigned long addr,
         vcpu->mmio_phys_addr = gpa;
         vcpu->mmio_size = bytes;
         vcpu->mmio_is_write = 1;
-        memcpy(vcpu->mmio_data, &val, bytes);
+        memcpy(vcpu->mmio_data, val, bytes);
 
         return X86EMUL_CONTINUE;
 }
 
 static int emulator_cmpxchg_emulated(unsigned long addr,
-                                     unsigned long old,
-                                     unsigned long new,
+                                     const void *old,
+                                     const void *new,
                                      unsigned int bytes,
                                      struct x86_emulate_ctxt *ctxt)
 {
@@ -1103,30 +1103,6 @@ static int emulator_cmpxchg_emulated(unsigned long addr,
         return emulator_write_emulated(addr, new, bytes, ctxt);
 }
 
-#ifdef CONFIG_X86_32
-
-static int emulator_cmpxchg8b_emulated(unsigned long addr,
-                                       unsigned long old_lo,
-                                       unsigned long old_hi,
-                                       unsigned long new_lo,
-                                       unsigned long new_hi,
-                                       struct x86_emulate_ctxt *ctxt)
-{
-        static int reported;
-        int r;
-
-        if (!reported) {
-                reported = 1;
-                printk(KERN_WARNING "kvm: emulating exchange8b as write\n");
-        }
-        r = emulator_write_emulated(addr, new_lo, 4, ctxt);
-        if (r != X86EMUL_CONTINUE)
-                return r;
-        return emulator_write_emulated(addr+4, new_hi, 4, ctxt);
-}
-
-#endif
-
 static unsigned long get_segment_base(struct kvm_vcpu *vcpu, int seg)
 {
         return kvm_arch_ops->get_segment_base(vcpu, seg);
@@ -1201,9 +1177,6 @@ struct x86_emulate_ops emulate_ops = {
         .read_emulated       = emulator_read_emulated,
         .write_emulated      = emulator_write_emulated,
         .cmpxchg_emulated    = emulator_cmpxchg_emulated,
-#ifdef CONFIG_X86_32
-        .cmpxchg8b_emulated  = emulator_cmpxchg8b_emulated,
-#endif
 };
 
 int emulate_instruction(struct kvm_vcpu *vcpu,
diff --git a/drivers/kvm/x86_emulate.c b/drivers/kvm/x86_emulate.c
index bcf872bdaf74..7ade09086aa5 100644
--- a/drivers/kvm/x86_emulate.c
+++ b/drivers/kvm/x86_emulate.c
@@ -1045,7 +1045,7 @@ done_prefixes:
                         if ((rc = ops->write_std(
                                      register_address(ctxt->ss_base,
                                                       _regs[VCPU_REGS_RSP]),
-                                     dst.val, dst.bytes, ctxt)) != 0)
+                                     &dst.val, dst.bytes, ctxt)) != 0)
                                 goto done;
                         dst.val = dst.orig_val; /* skanky: disable writeback */
                         break;
@@ -1078,12 +1078,12 @@ writeback:
                 case OP_MEM:
                         if (lock_prefix)
                                 rc = ops->cmpxchg_emulated((unsigned long)dst.
-                                                           ptr, dst.orig_val,
-                                                           dst.val, dst.bytes,
+                                                           ptr, &dst.orig_val,
+                                                           &dst.val, dst.bytes,
                                                            ctxt);
                         else
                                 rc = ops->write_emulated((unsigned long)dst.ptr,
-                                                         dst.val, dst.bytes,
+                                                         &dst.val, dst.bytes,
                                                          ctxt);
                         if (rc != 0)
                                 goto done;
@@ -1321,36 +1321,8 @@ twobyte_special_insn:
                 realmode_set_cr(ctxt->vcpu, modrm_reg, modrm_val, &_eflags);
                 break;
         case 0xc7:              /* Grp9 (cmpxchg8b) */
-#if defined(__i386__)
                 {
-                        unsigned long old_lo, old_hi;
-                        if (((rc = ops->read_emulated(cr2 + 0, &old_lo, 4,
-                                                      ctxt)) != 0)
-                            || ((rc = ops->read_emulated(cr2 + 4, &old_hi, 4,
-                                                         ctxt)) != 0))
-                                goto done;
-                        if ((old_lo != _regs[VCPU_REGS_RAX])
-                            || (old_hi != _regs[VCPU_REGS_RDX])) {
-                                _regs[VCPU_REGS_RAX] = old_lo;
-                                _regs[VCPU_REGS_RDX] = old_hi;
-                                _eflags &= ~EFLG_ZF;
-                        } else if (ops->cmpxchg8b_emulated == NULL) {
-                                rc = X86EMUL_UNHANDLEABLE;
-                                goto done;
-                        } else {
-                                if ((rc = ops->cmpxchg8b_emulated(cr2, old_lo,
-                                                          old_hi,
-                                                          _regs[VCPU_REGS_RBX],
-                                                          _regs[VCPU_REGS_RCX],
-                                                          ctxt)) != 0)
-                                        goto done;
-                                _eflags |= EFLG_ZF;
-                        }
-                        break;
-                }
-#elif defined(CONFIG_X86_64)
-                {
-                        unsigned long old, new;
+                        u64 old, new;
                         if ((rc = ops->read_emulated(cr2, &old, 8, ctxt)) != 0)
                                 goto done;
                         if (((u32) (old >> 0) != (u32) _regs[VCPU_REGS_RAX]) ||
@@ -1359,15 +1331,15 @@ twobyte_special_insn:
                                 _regs[VCPU_REGS_RDX] = (u32) (old >> 32);
                                 _eflags &= ~EFLG_ZF;
                         } else {
-                                new = (_regs[VCPU_REGS_RCX] << 32) | (u32) _regs[VCPU_REGS_RBX];
-                                if ((rc = ops->cmpxchg_emulated(cr2, old,
-                                                          new, 8, ctxt)) != 0)
+                                new = ((u64)_regs[VCPU_REGS_RCX] << 32)
+                                        | (u32) _regs[VCPU_REGS_RBX];
+                                if ((rc = ops->cmpxchg_emulated(cr2, &old,
+                                                          &new, 8, ctxt)) != 0)
                                         goto done;
                                 _eflags |= EFLG_ZF;
                         }
                         break;
                 }
-#endif
         }
         goto writeback;
 
diff --git a/drivers/kvm/x86_emulate.h b/drivers/kvm/x86_emulate.h
index 5d41bd55125e..ea3407d7feee 100644
--- a/drivers/kvm/x86_emulate.h
+++ b/drivers/kvm/x86_emulate.h
@@ -59,8 +59,7 @@ struct x86_emulate_ops {
          *  @val:   [OUT] Value read from memory, zero-extended to 'u_long'.
          *  @bytes: [IN ] Number of bytes to read from memory.
          */
-        int (*read_std)(unsigned long addr,
-                        unsigned long *val,
+        int (*read_std)(unsigned long addr, void *val,
                         unsigned int bytes, struct x86_emulate_ctxt * ctxt);
 
         /*
@@ -71,8 +70,7 @@ struct x86_emulate_ops {
          *                required).
          *  @bytes: [IN ] Number of bytes to write to memory.
          */
-        int (*write_std)(unsigned long addr,
-                         unsigned long val,
+        int (*write_std)(unsigned long addr, const void *val,
                          unsigned int bytes, struct x86_emulate_ctxt * ctxt);
 
         /*
@@ -82,7 +80,7 @@ struct x86_emulate_ops {
          *  @bytes: [IN ] Number of bytes to read from memory.
          */
         int (*read_emulated) (unsigned long addr,
-                              unsigned long *val,
+                              void *val,
                               unsigned int bytes,
                               struct x86_emulate_ctxt * ctxt);
 
@@ -94,7 +92,7 @@ struct x86_emulate_ops {
          *  @bytes: [IN ] Number of bytes to write to memory.
          */
         int (*write_emulated) (unsigned long addr,
-                               unsigned long val,
+                               const void *val,
                                unsigned int bytes,
                                struct x86_emulate_ctxt * ctxt);
 
@@ -107,29 +105,11 @@ struct x86_emulate_ops {
          *  @bytes: [IN ] Number of bytes to access using CMPXCHG.
          */
         int (*cmpxchg_emulated) (unsigned long addr,
-                                 unsigned long old,
-                                 unsigned long new,
+                                 const void *old,
+                                 const void *new,
                                  unsigned int bytes,
                                  struct x86_emulate_ctxt * ctxt);
 
-        /*
-         * cmpxchg8b_emulated: Emulate an atomic (LOCKed) CMPXCHG8B operation on an
-         *                     emulated/special memory area.
-         *  @addr:  [IN ] Linear address to access.
-         *  @old:   [IN ] Value expected to be current at @addr.
-         *  @new:   [IN ] Value to write to @addr.
-         * NOTES:
-         *  1. This function is only ever called when emulating a real CMPXCHG8B.
-         *  2. This function is *never* called on x86/64 systems.
-         *  2. Not defining this function (i.e., specifying NULL) is equivalent
-         *     to defining a function that always returns X86EMUL_UNHANDLEABLE.
-         */
-        int (*cmpxchg8b_emulated) (unsigned long addr,
-                                   unsigned long old_lo,
-                                   unsigned long old_hi,
-                                   unsigned long new_lo,
-                                   unsigned long new_hi,
-                                   struct x86_emulate_ctxt * ctxt);
 };
 
 struct cpu_user_regs;