Introduce write_readonly_mem in mmio-exit-info to indicate this exit is
caused by write access on readonly memslot

Signed-off-by: Xiao Guangrong <xiaoguangr...@linux.vnet.ibm.com>
---
 arch/x86/kvm/x86.c       |   12 ++++++++----
 include/linux/kvm.h      |    3 +++
 include/linux/kvm_host.h |    1 +
 virt/kvm/kvm_main.c      |    3 +++
 4 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 8cde327..5e10482 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3704,9 +3704,10 @@ int emulator_write_phys(struct kvm_vcpu *vcpu, gpa_t gpa,

        ret = kvm_write_guest(vcpu->kvm, gpa, val, bytes);
        if (ret < 0)
-               return 0;
+               return ret;
+
        kvm_mmu_pte_write(vcpu, gpa, val, bytes);
-       return 1;
+       return 0;
 }

 struct read_write_emulator_ops {
@@ -3736,7 +3737,7 @@ static int read_prepare(struct kvm_vcpu *vcpu, void *val, 
int bytes)
 static int read_emulate(struct kvm_vcpu *vcpu, gpa_t gpa,
                        void *val, int bytes)
 {
-       return !kvm_read_guest(vcpu->kvm, gpa, val, bytes);
+       return kvm_read_guest(vcpu->kvm, gpa, val, bytes);
 }

 static int write_emulate(struct kvm_vcpu *vcpu, gpa_t gpa,
@@ -3798,7 +3799,8 @@ static int emulator_read_write_onepage(unsigned long 
addr, void *val,
        if (ret)
                goto mmio;

-       if (ops->read_write_emulate(vcpu, gpa, val, bytes))
+       ret = ops->read_write_emulate(vcpu, gpa, val, bytes);
+       if (!ret)
                return X86EMUL_CONTINUE;

 mmio:
@@ -3820,6 +3822,7 @@ mmio:
                frag->gpa = gpa;
                frag->data = val;
                frag->len = now;
+               frag->write_readonly_mem = (ret == -EPERM);

                gpa += now;
                val += now;
@@ -3837,6 +3840,7 @@ static void set_mmio_exit_info(struct kvm_vcpu *vcpu,
        run->mmio.phys_addr = frag->gpa;
        run->mmio.len = frag->len;
        run->mmio.is_write = vcpu->mmio_is_write = write;
+       run->mmio.write_readonly_mem = frag->write_readonly_mem;

        if (write)
                memcpy(run->mmio.data, frag->data, frag->len);
diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index 94867d0..9261541 100644
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -222,6 +222,9 @@ struct kvm_run {
                        __u8  data[8];
                        __u32 len;
                        __u8  is_write;
+#ifdef __KVM_HAVE_READONLY_MEM
+                       __u8 write_readonly_mem;
+#endif
                } mmio;
                /* KVM_EXIT_HYPERCALL */
                struct {
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 2df6861..c47979d 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -184,6 +184,7 @@ struct kvm_mmio_fragment {
        gpa_t gpa;
        void *data;
        unsigned len;
+       bool write_readonly_mem;
 };

 struct kvm_vcpu {
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 5e899d9..d0babc9 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1445,6 +1445,9 @@ int kvm_write_guest_page(struct kvm *kvm, gfn_t gfn, 
const void *data,
        unsigned long addr;

        addr = gfn_to_hva(kvm, gfn);
+       if (addr == KVM_HVA_ERR_RO_BAD)
+               return -EPERM;
+
        if (kvm_is_error_hva(addr))
                return -EFAULT;
        r = __copy_to_user((void __user *)addr + offset, data, len);
-- 
1.7.7.6

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