KVM: SVM: Don't use kmap_atomic in nested_svm_map

Use of kmap_atomic disables preemption but if we run in
shadow-shadow mode the vmrun emulation executes kvm_set_cr3
which might sleep or fault. So use kmap instead for
nested_svm_map.

Cc: stable@kernel.org
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 24 insertions, 23 deletions

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 77fa2e3053b5..f9da35b06ec7 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -1423,7 +1423,7 @@ static inline int nested_svm_intr(struct vcpu_svm *svm)
         return 0;
 }
 
-static void *nested_svm_map(struct vcpu_svm *svm, u64 gpa, enum km_type idx)
+static void *nested_svm_map(struct vcpu_svm *svm, u64 gpa, struct page **_page)
 {
         struct page *page;
 
@@ -1431,7 +1431,9 @@ static void *nested_svm_map(struct vcpu_svm *svm, u64 gpa, enum km_type idx)
         if (is_error_page(page))
                 goto error;
 
-        return kmap_atomic(page, idx);
+        *_page = page;
+
+        return kmap(page);
 
 error:
         kvm_release_page_clean(page);
@@ -1440,16 +1442,9 @@ error:
         return NULL;
 }
 
-static void nested_svm_unmap(void *addr, enum km_type idx)
+static void nested_svm_unmap(struct page *page)
 {
-        struct page *page;
-
-        if (!addr)
-                return;
-
-        page = kmap_atomic_to_page(addr);
-
-        kunmap_atomic(addr, idx);
+        kunmap(page);
         kvm_release_page_dirty(page);
 }
 
@@ -1457,6 +1452,7 @@ static bool nested_svm_exit_handled_msr(struct vcpu_svm *svm)
 {
         u32 param = svm->vmcb->control.exit_info_1 & 1;
         u32 msr = svm->vcpu.arch.regs[VCPU_REGS_RCX];
+        struct page *page;
         bool ret = false;
         u32 t0, t1;
         u8 *msrpm;
@@ -1464,7 +1460,7 @@ static bool nested_svm_exit_handled_msr(struct vcpu_svm *svm)
         if (!(svm->nested.intercept & (1ULL << INTERCEPT_MSR_PROT)))
                 return false;
 
-        msrpm = nested_svm_map(svm, svm->nested.vmcb_msrpm, KM_USER0);
+        msrpm = nested_svm_map(svm, svm->nested.vmcb_msrpm, &page);
 
         if (!msrpm)
                 goto out;
@@ -1492,7 +1488,7 @@ static bool nested_svm_exit_handled_msr(struct vcpu_svm *svm)
         ret = msrpm[t1] & ((1 << param) << t0);
 
 out:
-        nested_svm_unmap(msrpm, KM_USER0);
+        nested_svm_unmap(page);
 
         return ret;
 }
@@ -1615,6 +1611,7 @@ static int nested_svm_vmexit(struct vcpu_svm *svm)
         struct vmcb *nested_vmcb;
         struct vmcb *hsave = svm->nested.hsave;
         struct vmcb *vmcb = svm->vmcb;
+        struct page *page;
 
         trace_kvm_nested_vmexit_inject(vmcb->control.exit_code,
                                        vmcb->control.exit_info_1,
@@ -1622,7 +1619,7 @@ static int nested_svm_vmexit(struct vcpu_svm *svm)
                                        vmcb->control.exit_int_info,
                                        vmcb->control.exit_int_info_err);
 
-        nested_vmcb = nested_svm_map(svm, svm->nested.vmcb, KM_USER0);
+        nested_vmcb = nested_svm_map(svm, svm->nested.vmcb, &page);
         if (!nested_vmcb)
                 return 1;
 
@@ -1712,7 +1709,7 @@ static int nested_svm_vmexit(struct vcpu_svm *svm)
         /* Exit nested SVM mode */
         svm->nested.vmcb = 0;
 
-        nested_svm_unmap(nested_vmcb, KM_USER0);
+        nested_svm_unmap(page);
 
         kvm_mmu_reset_context(&svm->vcpu);
         kvm_mmu_load(&svm->vcpu);
@@ -1723,9 +1720,10 @@ static int nested_svm_vmexit(struct vcpu_svm *svm)
 static bool nested_svm_vmrun_msrpm(struct vcpu_svm *svm)
 {
         u32 *nested_msrpm;
+        struct page *page;
         int i;
 
-        nested_msrpm = nested_svm_map(svm, svm->nested.vmcb_msrpm, KM_USER0);
+        nested_msrpm = nested_svm_map(svm, svm->nested.vmcb_msrpm, &page);
         if (!nested_msrpm)
                 return false;
 
@@ -1734,7 +1732,7 @@ static bool nested_svm_vmrun_msrpm(struct vcpu_svm *svm)
 
         svm->vmcb->control.msrpm_base_pa = __pa(svm->nested.msrpm);
 
-        nested_svm_unmap(nested_msrpm, KM_USER0);
+        nested_svm_unmap(page);
 
         return true;
 }
@@ -1744,8 +1742,9 @@ static bool nested_svm_vmrun(struct vcpu_svm *svm)
         struct vmcb *nested_vmcb;
         struct vmcb *hsave = svm->nested.hsave;
         struct vmcb *vmcb = svm->vmcb;
+        struct page *page;
 
-        nested_vmcb = nested_svm_map(svm, svm->vmcb->save.rax, KM_USER0);
+        nested_vmcb = nested_svm_map(svm, svm->vmcb->save.rax, &page);
         if (!nested_vmcb)
                 return false;
 
@@ -1857,7 +1856,7 @@ static bool nested_svm_vmrun(struct vcpu_svm *svm)
         svm->vmcb->control.event_inj = nested_vmcb->control.event_inj;
         svm->vmcb->control.event_inj_err = nested_vmcb->control.event_inj_err;
 
-        nested_svm_unmap(nested_vmcb, KM_USER0);
+        nested_svm_unmap(page);
 
         enable_gif(svm);
 
@@ -1883,6 +1882,7 @@ static void nested_svm_vmloadsave(struct vmcb *from_vmcb, struct vmcb *to_vmcb)
 static int vmload_interception(struct vcpu_svm *svm)
 {
         struct vmcb *nested_vmcb;
+        struct page *page;
 
         if (nested_svm_check_permissions(svm))
                 return 1;
@@ -1890,12 +1890,12 @@ static int vmload_interception(struct vcpu_svm *svm)
         svm->next_rip = kvm_rip_read(&svm->vcpu) + 3;
         skip_emulated_instruction(&svm->vcpu);
 
-        nested_vmcb = nested_svm_map(svm, svm->vmcb->save.rax, KM_USER0);
+        nested_vmcb = nested_svm_map(svm, svm->vmcb->save.rax, &page);
         if (!nested_vmcb)
                 return 1;
 
         nested_svm_vmloadsave(nested_vmcb, svm->vmcb);
-        nested_svm_unmap(nested_vmcb, KM_USER0);
+        nested_svm_unmap(page);
 
         return 1;
 }
@@ -1903,6 +1903,7 @@ static int vmload_interception(struct vcpu_svm *svm)
 static int vmsave_interception(struct vcpu_svm *svm)
 {
         struct vmcb *nested_vmcb;
+        struct page *page;
 
         if (nested_svm_check_permissions(svm))
                 return 1;
@@ -1910,12 +1911,12 @@ static int vmsave_interception(struct vcpu_svm *svm)
         svm->next_rip = kvm_rip_read(&svm->vcpu) + 3;
         skip_emulated_instruction(&svm->vcpu);
 
-        nested_vmcb = nested_svm_map(svm, svm->vmcb->save.rax, KM_USER0);
+        nested_vmcb = nested_svm_map(svm, svm->vmcb->save.rax, &page);
         if (!nested_vmcb)
                 return 1;
 
         nested_svm_vmloadsave(svm->vmcb, nested_vmcb);
-        nested_svm_unmap(nested_vmcb, KM_USER0);
+        nested_svm_unmap(page);
 
         return 1;
 }