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>

diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index 911c817..6755403 100644 (file)
--- 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 bcf872b..7ade090 100644 (file)
--- 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 5d41bd5..ea3407d 100644 (file)
--- 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;