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Subject[178/200] KVM: SVM: Dont use kmap_atomic in nested_svm_map
2.6.34-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Joerg Roedel <joerg.roedel@amd.com>

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

(Cherry-picked from commit 7597f129d8b6799da7a264e6d6f7401668d3a36d)
---
arch/x86/kvm/svm.c | 47 ++++++++++++++++++++++++-----------------------
1 file changed, 24 insertions(+), 23 deletions(-)

--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -1423,7 +1423,7 @@ static inline int nested_svm_intr(struct
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_
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(
{
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(
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(
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
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
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
/* 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
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(struc

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
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->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
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 vc
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 vc
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 vc
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;
}



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