KVM: introduce kvm_read_guest_virt, kvm_write_guest_virt

This commit change the name of emulator_read_std into kvm_read_guest_virt,
and add new function name kvm_write_guest_virt that allow writing into a
guest virtual address.

Signed-off-by: Izik Eidus <ieidus@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 9efc446b5ac6c094c86ad16298d678510fd734b1..b74576aec19acaac7ae11f3deeb01d8459b7c38c 100644 (file)
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -609,10 +609,6 @@ void kvm_inject_nmi(struct kvm_vcpu *vcpu);
 
 void fx_init(struct kvm_vcpu *vcpu);
 
-int emulator_read_std(unsigned long addr,
-                     void *val,
-                     unsigned int bytes,
-                     struct kvm_vcpu *vcpu);
 int emulator_write_emulated(unsigned long addr,
                            const void *val,
                            unsigned int bytes,

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 3b2acfd72d7f7ac59fddfd206265d06f6cd11c37..67f91764e99b99f00026326375e96837b7fdfaa2 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1976,10 +1976,8 @@ static struct kvm_io_device *vcpu_find_mmio_dev(struct kvm_vcpu *vcpu,
        return dev;
 }
 
-int emulator_read_std(unsigned long addr,
-                            void *val,
-                            unsigned int bytes,
-                            struct kvm_vcpu *vcpu)
+int kvm_read_guest_virt(gva_t addr, void *val, unsigned int bytes,
+                       struct kvm_vcpu *vcpu)
 {
        void *data = val;
        int r = X86EMUL_CONTINUE;
@@ -1987,27 +1985,57 @@ int emulator_read_std(unsigned long addr,
        while (bytes) {
                gpa_t gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, addr);
                unsigned offset = addr & (PAGE_SIZE-1);
-               unsigned tocopy = min(bytes, (unsigned)PAGE_SIZE - offset);
+               unsigned toread = min(bytes, (unsigned)PAGE_SIZE - offset);
                int ret;
 
                if (gpa == UNMAPPED_GVA) {
                        r = X86EMUL_PROPAGATE_FAULT;
                        goto out;
                }
-               ret = kvm_read_guest(vcpu->kvm, gpa, data, tocopy);
+               ret = kvm_read_guest(vcpu->kvm, gpa, data, toread);
                if (ret < 0) {
                        r = X86EMUL_UNHANDLEABLE;
                        goto out;
                }
 
-               bytes -= tocopy;
-               data += tocopy;
-               addr += tocopy;
+               bytes -= toread;
+               data += toread;
+               addr += toread;
        }
 out:
        return r;
 }
-EXPORT_SYMBOL_GPL(emulator_read_std);
+
+int kvm_write_guest_virt(gva_t addr, void *val, unsigned int bytes,
+                        struct kvm_vcpu *vcpu)
+{
+       void *data = val;
+       int r = X86EMUL_CONTINUE;
+
+       while (bytes) {
+               gpa_t gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, addr);
+               unsigned offset = addr & (PAGE_SIZE-1);
+               unsigned towrite = min(bytes, (unsigned)PAGE_SIZE - offset);
+               int ret;
+
+               if (gpa == UNMAPPED_GVA) {
+                       r = X86EMUL_PROPAGATE_FAULT;
+                       goto out;
+               }
+               ret = kvm_write_guest(vcpu->kvm, gpa, data, towrite);
+               if (ret < 0) {
+                       r = X86EMUL_UNHANDLEABLE;
+                       goto out;
+               }
+
+               bytes -= towrite;
+               data += towrite;
+               addr += towrite;
+       }
+out:
+       return r;
+}
+
 
 static int emulator_read_emulated(unsigned long addr,
                                  void *val,
@@ -2029,8 +2057,8 @@ static int emulator_read_emulated(unsigned long addr,
        if ((gpa & PAGE_MASK) == APIC_DEFAULT_PHYS_BASE)
                goto mmio;
 
-       if (emulator_read_std(addr, val, bytes, vcpu)
-                       == X86EMUL_CONTINUE)
+       if (kvm_read_guest_virt(addr, val, bytes, vcpu)
+                               == X86EMUL_CONTINUE)
                return X86EMUL_CONTINUE;
        if (gpa == UNMAPPED_GVA)
                return X86EMUL_PROPAGATE_FAULT;
@@ -2233,7 +2261,7 @@ void kvm_report_emulation_failure(struct kvm_vcpu *vcpu, const char *context)
 
        rip_linear = rip + get_segment_base(vcpu, VCPU_SREG_CS);
 
-       emulator_read_std(rip_linear, (void *)opcodes, 4, vcpu);
+       kvm_read_guest_virt(rip_linear, (void *)opcodes, 4, vcpu);
 
        printk(KERN_ERR "emulation failed (%s) rip %lx %02x %02x %02x %02x\n",
               context, rip, opcodes[0], opcodes[1], opcodes[2], opcodes[3]);
@@ -2241,7 +2269,7 @@ void kvm_report_emulation_failure(struct kvm_vcpu *vcpu, const char *context)
 EXPORT_SYMBOL_GPL(kvm_report_emulation_failure);
 
 static struct x86_emulate_ops emulate_ops = {
-       .read_std            = emulator_read_std,
+       .read_std            = kvm_read_guest_virt,
        .read_emulated       = emulator_read_emulated,
        .write_emulated      = emulator_write_emulated,
        .cmpxchg_emulated    = emulator_cmpxchg_emulated,