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* [PATCH 0/3 v2] KVM: nSVM: Check addresses of MSR bitmap and IO bitmap tables on vmrun of nested guests
@ 2021-01-16  2:20 Krish Sadhukhan
  2021-01-16  2:20 ` [PATCH 1/3 v2] nSVM: Check addresses of MSR and IO bitmap Krish Sadhukhan
                   ` (2 more replies)
  0 siblings, 3 replies; 6+ messages in thread
From: Krish Sadhukhan @ 2021-01-16  2:20 UTC (permalink / raw)
  To: kvm; +Cc: pbonzini, jmattson, seanjc

v1 -> v2:
	In patch# 1, the parameter to nested_vmcb_check_controls() has been
	changed to 'struct kvm_vcpu' from 'struct vcpu_svm'. This necessiated
	relevant changes to its callers.
	Also, the new checks in nested_vmcb_check_controls() now use
	page_address_valid() instead of duplicating code.

	It has also been rebased to v5.11-rc3.


[PATCH 1/3 v2] nSVM: Check addresses of MSR and IO bitmap
[PATCH 2/3 v2] Test: nSVM: Test MSR and IO bitmap address
[PATCH 3/3 v2] Test: SVM: Use ALIGN macro when aligning 'io_bitmap_area'

 arch/x86/kvm/svm/nested.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

Krish Sadhukhan (1):
      nSVM: Check addresses of MSR and IO bitmap

 x86/svm.c       |  2 +-
 x86/svm_tests.c | 38 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 39 insertions(+), 1 deletion(-)

Krish Sadhukhan (2):
      nSVM: Test MSR and IO bitmap address
      SVM: Use ALIGN macro when aligning 'io_bitmap_area'


^ permalink raw reply	[flat|nested] 6+ messages in thread

* [PATCH 1/3 v2] nSVM: Check addresses of MSR and IO bitmap
  2021-01-16  2:20 [PATCH 0/3 v2] KVM: nSVM: Check addresses of MSR bitmap and IO bitmap tables on vmrun of nested guests Krish Sadhukhan
@ 2021-01-16  2:20 ` Krish Sadhukhan
  2021-01-20  0:45   ` Sean Christopherson
  2021-01-16  2:20 ` [PATCH 2/3 v2] Test: nSVM: Test MSR and IO bitmap address Krish Sadhukhan
  2021-01-16  2:20 ` [PATCH 3/3 v2] Test: SVM: Use ALIGN macro when aligning 'io_bitmap_area' Krish Sadhukhan
  2 siblings, 1 reply; 6+ messages in thread
From: Krish Sadhukhan @ 2021-01-16  2:20 UTC (permalink / raw)
  To: kvm; +Cc: pbonzini, jmattson, seanjc

According to section "Canonicalization and Consistency Checks" in APM vol 2,
the following guest state is illegal:

        "The MSR or IOIO intercept tables extend to a physical address that
         is greater than or equal to the maximum supported physical address."

Also check that these addresses are aligned on page boundary.

Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
---
 arch/x86/kvm/svm/nested.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index cb4c6ee10029..2419f392a13d 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -211,7 +211,8 @@ static bool svm_get_nested_state_pages(struct kvm_vcpu *vcpu)
 	return true;
 }
 
-static bool nested_vmcb_check_controls(struct vmcb_control_area *control)
+static bool nested_vmcb_check_controls(struct kvm_vcpu *vcpu,
+				       struct vmcb_control_area *control)
 {
 	if ((vmcb_is_intercept(control, INTERCEPT_VMRUN)) == 0)
 		return false;
@@ -223,10 +224,15 @@ static bool nested_vmcb_check_controls(struct vmcb_control_area *control)
 	    !npt_enabled)
 		return false;
 
+	if (!page_address_valid(vcpu, control->msrpm_base_pa))
+		return false;
+	if (!page_address_valid(vcpu, control->iopm_base_pa))
+		return false;
+
 	return true;
 }
 
-static bool nested_vmcb_checks(struct vcpu_svm *svm, struct vmcb *vmcb12)
+static bool nested_vmcb_checks(struct kvm_vcpu *vcpu, struct vmcb *vmcb12)
 {
 	bool vmcb12_lma;
 
@@ -255,10 +261,10 @@ static bool nested_vmcb_checks(struct vcpu_svm *svm, struct vmcb *vmcb12)
 		    (vmcb12->save.cr3 & MSR_CR3_LONG_MBZ_MASK))
 			return false;
 	}
-	if (!kvm_is_valid_cr4(&svm->vcpu, vmcb12->save.cr4))
+	if (!kvm_is_valid_cr4(vcpu, vmcb12->save.cr4))
 		return false;
 
-	return nested_vmcb_check_controls(&vmcb12->control);
+	return nested_vmcb_check_controls(vcpu, &vmcb12->control);
 }
 
 static void load_nested_vmcb_control(struct vcpu_svm *svm,
@@ -485,7 +491,7 @@ int nested_svm_vmrun(struct vcpu_svm *svm)
 	if (WARN_ON_ONCE(!svm->nested.initialized))
 		return -EINVAL;
 
-	if (!nested_vmcb_checks(svm, vmcb12)) {
+	if (!nested_vmcb_checks(&svm->vcpu, vmcb12)) {
 		vmcb12->control.exit_code    = SVM_EXIT_ERR;
 		vmcb12->control.exit_code_hi = 0;
 		vmcb12->control.exit_info_1  = 0;
@@ -1173,7 +1179,7 @@ static int svm_set_nested_state(struct kvm_vcpu *vcpu,
 		goto out_free;
 
 	ret = -EINVAL;
-	if (!nested_vmcb_check_controls(ctl))
+	if (!nested_vmcb_check_controls(vcpu, ctl))
 		goto out_free;
 
 	/*
-- 
2.27.0


^ permalink raw reply	[flat|nested] 6+ messages in thread

* [PATCH 2/3 v2] Test: nSVM: Test MSR and IO bitmap address
  2021-01-16  2:20 [PATCH 0/3 v2] KVM: nSVM: Check addresses of MSR bitmap and IO bitmap tables on vmrun of nested guests Krish Sadhukhan
  2021-01-16  2:20 ` [PATCH 1/3 v2] nSVM: Check addresses of MSR and IO bitmap Krish Sadhukhan
@ 2021-01-16  2:20 ` Krish Sadhukhan
  2021-01-16  2:20 ` [PATCH 3/3 v2] Test: SVM: Use ALIGN macro when aligning 'io_bitmap_area' Krish Sadhukhan
  2 siblings, 0 replies; 6+ messages in thread
From: Krish Sadhukhan @ 2021-01-16  2:20 UTC (permalink / raw)
  To: kvm; +Cc: pbonzini, jmattson, seanjc

According to section "Canonicalization and Consistency Checks" in APM vol 2,
the following guest state is illegal:

    "The MSR or IOIO intercept tables extend to a physical address that
     is greater than or equal to the maximum supported physical address."

Also test that these addresses are aligned on page boundary.

Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
---
 x86/svm_tests.c | 38 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/x86/svm_tests.c b/x86/svm_tests.c
index dc86efd..929a3e1 100644
--- a/x86/svm_tests.c
+++ b/x86/svm_tests.c
@@ -2304,6 +2304,43 @@ static void test_dr(void)
 	vmcb->save.dr7 = dr_saved;
 }
 
+extern u8 msr_bitmap_area[];
+extern u8 io_bitmap_area[];
+
+#define TEST_BITMAP_ADDR(prot_type, bitmap_addr, msg)  {                \
+	vmcb->control.intercept = 1ULL << prot_type;                    \
+	addr_unalign = virt_to_phys(bitmap_addr);                       \
+	if (prot_type == INTERCEPT_MSR_PROT)                            \
+		vmcb->control.msrpm_base_pa = addr_unalign;             \
+	else                                                            \
+		vmcb->control.iopm_base_pa = addr_unalign;              \
+	report(svm_vmrun() == SVM_EXIT_ERR, "Test %s address: %lx", msg,\
+	    addr_unalign);                                              \
+	vmcb->control.msrpm_base_pa = addr_spill_beyond_ram;            \
+	report(svm_vmrun() == SVM_EXIT_ERR, "Test %s address: %lx", msg,\
+	    addr_spill_beyond_ram);                                     \
+}                                                                       \
+
+/*
+ * If the MSR or IOIO intercept table extends to a physical address that
+ * is greater than or equal to the maximum supported physical address, the
+ * guest state is illegal.
+ *
+ * [ APM vol 2]
+ */
+static void test_msrpm_iopm_bitmap_addrs(void)
+{
+	u64 addr_unalign;
+	u64 addr_spill_beyond_ram =
+	    (u64)(((u64)1 << cpuid_maxphyaddr()) - 4096);
+
+	/* MSR bitmap address */
+	TEST_BITMAP_ADDR(INTERCEPT_MSR_PROT, msr_bitmap_area, "MSRPM");
+
+	/* MSR bitmap address */
+	TEST_BITMAP_ADDR(INTERCEPT_IOIO_PROT, io_bitmap_area, "IOPM");
+}
+
 static void svm_guest_state_test(void)
 {
 	test_set_guest(basic_guest_main);
@@ -2313,6 +2350,7 @@ static void svm_guest_state_test(void)
 	test_cr3();
 	test_cr4();
 	test_dr();
+	test_msrpm_iopm_bitmap_addrs();
 }
 
 struct svm_test svm_tests[] = {
-- 
2.27.0


^ permalink raw reply	[flat|nested] 6+ messages in thread

* [PATCH 3/3 v2] Test: SVM: Use ALIGN macro when aligning 'io_bitmap_area'
  2021-01-16  2:20 [PATCH 0/3 v2] KVM: nSVM: Check addresses of MSR bitmap and IO bitmap tables on vmrun of nested guests Krish Sadhukhan
  2021-01-16  2:20 ` [PATCH 1/3 v2] nSVM: Check addresses of MSR and IO bitmap Krish Sadhukhan
  2021-01-16  2:20 ` [PATCH 2/3 v2] Test: nSVM: Test MSR and IO bitmap address Krish Sadhukhan
@ 2021-01-16  2:20 ` Krish Sadhukhan
  2 siblings, 0 replies; 6+ messages in thread
From: Krish Sadhukhan @ 2021-01-16  2:20 UTC (permalink / raw)
  To: kvm; +Cc: pbonzini, jmattson, seanjc

Since the macro is available and we already use it for MSR bitmap table, use
it for aligning IO bitmap table also.

Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
---
 x86/svm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/x86/svm.c b/x86/svm.c
index a1808c7..846cf2a 100644
--- a/x86/svm.c
+++ b/x86/svm.c
@@ -298,7 +298,7 @@ static void setup_svm(void)
 	wrmsr(MSR_EFER, rdmsr(MSR_EFER) | EFER_SVME);
 	wrmsr(MSR_EFER, rdmsr(MSR_EFER) | EFER_NX);
 
-	io_bitmap = (void *) (((ulong)io_bitmap_area + 4095) & ~4095);
+	io_bitmap = (void *) ALIGN((ulong)io_bitmap_area, PAGE_SIZE);
 
 	msr_bitmap = (void *) ALIGN((ulong)msr_bitmap_area, PAGE_SIZE);
 
-- 
2.27.0


^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH 1/3 v2] nSVM: Check addresses of MSR and IO bitmap
  2021-01-16  2:20 ` [PATCH 1/3 v2] nSVM: Check addresses of MSR and IO bitmap Krish Sadhukhan
@ 2021-01-20  0:45   ` Sean Christopherson
  2021-01-21  0:36     ` Krish Sadhukhan
  0 siblings, 1 reply; 6+ messages in thread
From: Sean Christopherson @ 2021-01-20  0:45 UTC (permalink / raw)
  To: Krish Sadhukhan; +Cc: kvm, pbonzini, jmattson

On Sat, Jan 16, 2021, Krish Sadhukhan wrote:
> According to section "Canonicalization and Consistency Checks" in APM vol 2,
> the following guest state is illegal:
> 
>         "The MSR or IOIO intercept tables extend to a physical address that
>          is greater than or equal to the maximum supported physical address."
> 
> Also check that these addresses are aligned on page boundary.
> 
> Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
> ---
>  arch/x86/kvm/svm/nested.c | 18 ++++++++++++------
>  1 file changed, 12 insertions(+), 6 deletions(-)
> 
> diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
> index cb4c6ee10029..2419f392a13d 100644
> --- a/arch/x86/kvm/svm/nested.c
> +++ b/arch/x86/kvm/svm/nested.c
> @@ -211,7 +211,8 @@ static bool svm_get_nested_state_pages(struct kvm_vcpu *vcpu)
>  	return true;
>  }
>  
> -static bool nested_vmcb_check_controls(struct vmcb_control_area *control)
> +static bool nested_vmcb_check_controls(struct kvm_vcpu *vcpu,
> +				       struct vmcb_control_area *control)
>  {
>  	if ((vmcb_is_intercept(control, INTERCEPT_VMRUN)) == 0)
>  		return false;
> @@ -223,10 +224,15 @@ static bool nested_vmcb_check_controls(struct vmcb_control_area *control)
>  	    !npt_enabled)
>  		return false;
>  
> +	if (!page_address_valid(vcpu, control->msrpm_base_pa))
> +		return false;
> +	if (!page_address_valid(vcpu, control->iopm_base_pa))

These checks are wrong.  The MSRPM is 8kb in size, and the IOPM is 12kb, and the
APM explicitly states that the last byte is checked:

  if the address of the last byte in the table is greater than or equal to the
  maximum supported physical address, this is treated as illegal VMCB state and
  causes a #VMEXIT(VMEXIT_INVALID).

KVM can't check just the last byte, as that would fail to detect a wrap of the
64-bit boundary.  Might be worth adding yet another helper?  I think this will
work, though I'm sure Paolo has a much more clever solution :-)

  static inline bool page_range_valid(struct kvm_vcpu *vcpu, gpa_t gpa, int size)
  {
	gpa_t last_page = gpa + size - PAGE_SIZE;

	if (last_page < gpa)
		return false;

	return page_address_valid(last_page);
  }

Note, the IOPM is 12kb in size, but KVM allocates and initializes 16kb, i.e.
using IOPM_ALLOC_ORDER for the check would be wrong.  Maybe define the actual
size for both bitmaps and use get_order() instead of hardcoding the order?  That
would make it easy to "fix" svm_hardware_setup() so that it doesn't initialize
unused memory.

> +		return false;
> +
>  	return true;
>  }
>  
> -static bool nested_vmcb_checks(struct vcpu_svm *svm, struct vmcb *vmcb12)
> +static bool nested_vmcb_checks(struct kvm_vcpu *vcpu, struct vmcb *vmcb12)
>  {
>  	bool vmcb12_lma;
>  
> @@ -255,10 +261,10 @@ static bool nested_vmcb_checks(struct vcpu_svm *svm, struct vmcb *vmcb12)
>  		    (vmcb12->save.cr3 & MSR_CR3_LONG_MBZ_MASK))
>  			return false;
>  	}
> -	if (!kvm_is_valid_cr4(&svm->vcpu, vmcb12->save.cr4))
> +	if (!kvm_is_valid_cr4(vcpu, vmcb12->save.cr4))
>  		return false;
>  
> -	return nested_vmcb_check_controls(&vmcb12->control);
> +	return nested_vmcb_check_controls(vcpu, &vmcb12->control);
>  }
>  
>  static void load_nested_vmcb_control(struct vcpu_svm *svm,
> @@ -485,7 +491,7 @@ int nested_svm_vmrun(struct vcpu_svm *svm)
>  	if (WARN_ON_ONCE(!svm->nested.initialized))
>  		return -EINVAL;
>  
> -	if (!nested_vmcb_checks(svm, vmcb12)) {
> +	if (!nested_vmcb_checks(&svm->vcpu, vmcb12)) {
>  		vmcb12->control.exit_code    = SVM_EXIT_ERR;
>  		vmcb12->control.exit_code_hi = 0;
>  		vmcb12->control.exit_info_1  = 0;
> @@ -1173,7 +1179,7 @@ static int svm_set_nested_state(struct kvm_vcpu *vcpu,
>  		goto out_free;
>  
>  	ret = -EINVAL;
> -	if (!nested_vmcb_check_controls(ctl))
> +	if (!nested_vmcb_check_controls(vcpu, ctl))
>  		goto out_free;
>  
>  	/*
> -- 
> 2.27.0
> 

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH 1/3 v2] nSVM: Check addresses of MSR and IO bitmap
  2021-01-20  0:45   ` Sean Christopherson
@ 2021-01-21  0:36     ` Krish Sadhukhan
  0 siblings, 0 replies; 6+ messages in thread
From: Krish Sadhukhan @ 2021-01-21  0:36 UTC (permalink / raw)
  To: Sean Christopherson; +Cc: kvm, pbonzini, jmattson


On 1/19/21 4:45 PM, Sean Christopherson wrote:
> On Sat, Jan 16, 2021, Krish Sadhukhan wrote:
>> According to section "Canonicalization and Consistency Checks" in APM vol 2,
>> the following guest state is illegal:
>>
>>          "The MSR or IOIO intercept tables extend to a physical address that
>>           is greater than or equal to the maximum supported physical address."
>>
>> Also check that these addresses are aligned on page boundary.
>>
>> Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
>> ---
>>   arch/x86/kvm/svm/nested.c | 18 ++++++++++++------
>>   1 file changed, 12 insertions(+), 6 deletions(-)
>>
>> diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
>> index cb4c6ee10029..2419f392a13d 100644
>> --- a/arch/x86/kvm/svm/nested.c
>> +++ b/arch/x86/kvm/svm/nested.c
>> @@ -211,7 +211,8 @@ static bool svm_get_nested_state_pages(struct kvm_vcpu *vcpu)
>>   	return true;
>>   }
>>   
>> -static bool nested_vmcb_check_controls(struct vmcb_control_area *control)
>> +static bool nested_vmcb_check_controls(struct kvm_vcpu *vcpu,
>> +				       struct vmcb_control_area *control)
>>   {
>>   	if ((vmcb_is_intercept(control, INTERCEPT_VMRUN)) == 0)
>>   		return false;
>> @@ -223,10 +224,15 @@ static bool nested_vmcb_check_controls(struct vmcb_control_area *control)
>>   	    !npt_enabled)
>>   		return false;
>>   
>> +	if (!page_address_valid(vcpu, control->msrpm_base_pa))
>> +		return false;
>> +	if (!page_address_valid(vcpu, control->iopm_base_pa))
> These checks are wrong.  The MSRPM is 8kb in size, and the IOPM is 12kb, and the
> APM explicitly states that the last byte is checked:
>
>    if the address of the last byte in the table is greater than or equal to the
>    maximum supported physical address, this is treated as illegal VMCB state and
>    causes a #VMEXIT(VMEXIT_INVALID).
>
> KVM can't check just the last byte, as that would fail to detect a wrap of the
> 64-bit boundary.  Might be worth adding yet another helper?  I think this will
> work, though I'm sure Paolo has a much more clever solution :-)
>
>    static inline bool page_range_valid(struct kvm_vcpu *vcpu, gpa_t gpa, int size)
>    {
> 	gpa_t last_page = gpa + size - PAGE_SIZE;
>
> 	if (last_page < gpa)
> 		return false;
>
> 	return page_address_valid(last_page);
>    }
>
> Note, the IOPM is 12kb in size, but KVM allocates and initializes 16kb, i.e.
> using IOPM_ALLOC_ORDER for the check would be wrong.  Maybe define the actual
> size for both bitmaps and use get_order() instead of hardcoding the order?  That
> would make it easy to "fix" svm_hardware_setup() so that it doesn't initialize
> unused memory.


Is there any issues with using alloc_pages_exact() instead of 
alloc_pages() for allocating the IOPM bitmap ?

>
>> +		return false;
>> +
>>   	return true;
>>   }
>>   
>> -static bool nested_vmcb_checks(struct vcpu_svm *svm, struct vmcb *vmcb12)
>> +static bool nested_vmcb_checks(struct kvm_vcpu *vcpu, struct vmcb *vmcb12)
>>   {
>>   	bool vmcb12_lma;
>>   
>> @@ -255,10 +261,10 @@ static bool nested_vmcb_checks(struct vcpu_svm *svm, struct vmcb *vmcb12)
>>   		    (vmcb12->save.cr3 & MSR_CR3_LONG_MBZ_MASK))
>>   			return false;
>>   	}
>> -	if (!kvm_is_valid_cr4(&svm->vcpu, vmcb12->save.cr4))
>> +	if (!kvm_is_valid_cr4(vcpu, vmcb12->save.cr4))
>>   		return false;
>>   
>> -	return nested_vmcb_check_controls(&vmcb12->control);
>> +	return nested_vmcb_check_controls(vcpu, &vmcb12->control);
>>   }
>>   
>>   static void load_nested_vmcb_control(struct vcpu_svm *svm,
>> @@ -485,7 +491,7 @@ int nested_svm_vmrun(struct vcpu_svm *svm)
>>   	if (WARN_ON_ONCE(!svm->nested.initialized))
>>   		return -EINVAL;
>>   
>> -	if (!nested_vmcb_checks(svm, vmcb12)) {
>> +	if (!nested_vmcb_checks(&svm->vcpu, vmcb12)) {
>>   		vmcb12->control.exit_code    = SVM_EXIT_ERR;
>>   		vmcb12->control.exit_code_hi = 0;
>>   		vmcb12->control.exit_info_1  = 0;
>> @@ -1173,7 +1179,7 @@ static int svm_set_nested_state(struct kvm_vcpu *vcpu,
>>   		goto out_free;
>>   
>>   	ret = -EINVAL;
>> -	if (!nested_vmcb_check_controls(ctl))
>> +	if (!nested_vmcb_check_controls(vcpu, ctl))
>>   		goto out_free;
>>   
>>   	/*
>> -- 
>> 2.27.0
>>

^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2021-01-21  1:10 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-01-16  2:20 [PATCH 0/3 v2] KVM: nSVM: Check addresses of MSR bitmap and IO bitmap tables on vmrun of nested guests Krish Sadhukhan
2021-01-16  2:20 ` [PATCH 1/3 v2] nSVM: Check addresses of MSR and IO bitmap Krish Sadhukhan
2021-01-20  0:45   ` Sean Christopherson
2021-01-21  0:36     ` Krish Sadhukhan
2021-01-16  2:20 ` [PATCH 2/3 v2] Test: nSVM: Test MSR and IO bitmap address Krish Sadhukhan
2021-01-16  2:20 ` [PATCH 3/3 v2] Test: SVM: Use ALIGN macro when aligning 'io_bitmap_area' Krish Sadhukhan

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