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 <[email protected]>
---
 arch/x86/kvm/x86.c       |   23 ++++++++++++++---------
 include/linux/kvm.h      |    3 +++
 include/linux/kvm_host.h |    1 +
 virt/kvm/kvm_main.c      |    3 +++
 4 files changed, 21 insertions(+), 9 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 42bbf41..6d7fe4a 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3710,9 +3710,10 @@ 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 {
@@ -3742,7 +3743,7 @@ 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,
@@ -3807,7 +3808,8 @@ 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:
@@ -3829,6 +3831,7 @@ mmio:
                frag->gpa = gpa;
                frag->data = val;
                frag->len = now;
+               frag->write_readonly_mem = (ret == -EPERM);

                gpa += now;
                val += now;
@@ -3842,8 +3845,8 @@ int emulator_read_write(struct x86_emulate_ctxt *ctxt, 
unsigned long addr,
                        struct x86_exception *exception,
                        struct read_write_emulator_ops *ops)
 {
+       struct kvm_mmio_fragment *frag;
        struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt);
-       gpa_t gpa;
        int rc;

        if (ops->read_write_prepare &&
@@ -3875,17 +3878,18 @@ int emulator_read_write(struct x86_emulate_ctxt *ctxt, 
unsigned long addr,
        if (!vcpu->mmio_nr_fragments)
                return rc;

-       gpa = vcpu->mmio_fragments[0].gpa;
+       frag = &vcpu->mmio_fragments[0];

        vcpu->mmio_needed = 1;
        vcpu->mmio_cur_fragment = 0;

-       vcpu->run->mmio.len = vcpu->mmio_fragments[0].len;
+       vcpu->run->mmio.len = frag->len;
        vcpu->run->mmio.is_write = vcpu->mmio_is_write = ops->write;
        vcpu->run->exit_reason = KVM_EXIT_MMIO;
-       vcpu->run->mmio.phys_addr = gpa;
+       vcpu->run->mmio.phys_addr = frag->gpa;
+       vcpu->run->mmio.write_readonly_mem = frag->write_readonly_mem;

-       return ops->read_write_exit_mmio(vcpu, gpa, val, bytes);
+       return ops->read_write_exit_mmio(vcpu, frag->gpa, val, bytes);
 }

 static int emulator_read_emulated(struct x86_emulate_ctxt *ctxt,
@@ -5525,6 +5529,7 @@ static int complete_mmio(struct kvm_vcpu *vcpu)
                ++frag;
                run->exit_reason = KVM_EXIT_MMIO;
                run->mmio.phys_addr = frag->gpa;
+               vcpu->run->mmio.write_readonly_mem = frag->write_readonly_mem;
                if (vcpu->mmio_is_write)
                        memcpy(run->mmio.data, frag->data, frag->len);
                run->mmio.len = frag->len;
diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index d808694..9d8002f 100644
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -226,6 +226,9 @@ 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 5972c98..c37b225 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -189,6 +189,7 @@ 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 3416f8a..0c7def7 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1456,6 +1456,9 @@ 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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