[PATCH 0/4] KVM: nSVM: Check reserved bits in DR6, DR7 and EFER on vmrun of nested guests

[PATCH 0/4] KVM: nSVM: Check reserved bits in DR6, DR7 and EFER on vmrun of nested guests

[Krish Sadhukhan]

Patch# 1: Moves the check for upper 32 reserved bits of DR6 to a new function.
Patch# 2: Adds the KVM checks for DR6[63:32] and DR7[64:32] reserved bits
Patch# 3: Adds kvm-unit-tests for DR6[63:32] and DR7[64:32] reserved bits and
	  reserved bits in EFER
Patch# 4: Removes the duplicate definition of 'vmcb' that sneaked via one of
	  my previous patches.


[PATCH 1/4] KVM: x86: Move the check for upper 32 reserved bits of
[PATCH 2/4] KVM: nSVM: Check that DR6[63:32] and DR7[64:32] are not
[PATCH 3/4] kvm-unit-tests: nSVM: Test that DR6[63:32], DR7[63:32]
[PATCH 4/4] kvm-unit-tests: x86: Remove duplicate instance of 'vmcb'

 arch/x86/kvm/svm/nested.c | 3 +++
 arch/x86/kvm/x86.c        | 2 +-
 arch/x86/kvm/x86.h        | 5 +++++
 3 files changed, 9 insertions(+), 1 deletion(-)

Krish Sadhukhan (2):
      KVM: x86: Move the check for upper 32 reserved bits of DR6 to separate fun
      KVM: nVMX: Check that DR6[63:32] and DR7[64:32] are not set on vmrun of ne
 x86/svm.c       |  1 -
 x86/svm.h       |  3 +++
 x86/svm_tests.c | 59 ++++++++++++++++++++++++++++++++++++++-------------------
 3 files changed, 42 insertions(+), 21 deletions(-)

Krish Sadhukhan (2):
      kvm-unit-tests: nSVM: Test that DR6[63:32], DR7[63:32] and EFER reserved b
      kvm-unit-tests: x86: Remove duplicate instance of 'vmcb'

[PATCH 1/4] KVM: x86: Move the check for upper 32 reserved bits of DR6 to separate function

[Krish Sadhukhan]

Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
---
 arch/x86/kvm/x86.c | 2 +-
 arch/x86/kvm/x86.h | 5 +++++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index c17e6eb..4746ec1 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1096,7 +1096,7 @@ static int __kvm_set_dr(struct kvm_vcpu *vcpu, int dr, unsigned long val)
 	case 4:
 		/* fall through */
 	case 6:
-		if (val & 0xffffffff00000000ULL)
+		if (!kvm_dr6_valid(val))
 			return -1; /* #GP */
 		vcpu->arch.dr6 = (val & DR6_VOLATILE) | kvm_dr6_fixed(vcpu);
 		break;
diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
index b968acc..5043108 100644
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h
@@ -354,6 +354,11 @@ static inline bool kvm_dr7_valid(u64 data)
 	/* Bits [63:32] are reserved */
 	return !(data >> 32);
 }
+static inline bool kvm_dr6_valid(u64 data)
+{
+	/* Bits [63:32] are reserved */
+	return !(data >> 32);
+}
 
 void kvm_load_guest_xsave_state(struct kvm_vcpu *vcpu);
 void kvm_load_host_xsave_state(struct kvm_vcpu *vcpu);
-- 
1.8.3.1

[PATCH 2/4] KVM: nSVM: Check that DR6[63:32] and DR7[64:32] are not set on vmrun of nested guests

[Krish Sadhukhan]

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

    "DR6[63:32] are not zero."
    "DR7[63:32] are not zero."
    "Any MBZ bit of EFER is set."

Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
---
 arch/x86/kvm/svm/nested.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index 9a2a62e..2fec51d 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -208,6 +208,9 @@ static bool nested_vmcb_checks(struct vmcb *vmcb)
 	if ((vmcb->save.efer & EFER_SVME) == 0)
 		return false;
 
+	if (!kvm_dr6_valid(vmcb->save.dr6) || !kvm_dr7_valid(vmcb->save.dr7))
+		return false;
+
 	if ((vmcb->control.intercept & (1ULL << INTERCEPT_VMRUN)) == 0)
 		return false;
 
-- 
1.8.3.1

[PATCH 3/4] kvm-unit-tests: nSVM: Test that DR6[63:32], DR7[63:32] and EFER reserved bits are not set on vmrun of nested guests

[Krish Sadhukhan]

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

    "DR6[63:32] are not zero."
    "DR7[63:32] are not zero."
    "Any MBZ bit of EFER is set."

Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
---
 x86/svm.h       |  3 +++
 x86/svm_tests.c | 59 ++++++++++++++++++++++++++++++++++++++-------------------
 2 files changed, 42 insertions(+), 20 deletions(-)

diff --git a/x86/svm.h b/x86/svm.h
index 3d5b79c..14418ef 100644
--- a/x86/svm.h
+++ b/x86/svm.h
@@ -329,6 +329,9 @@ struct __attribute__ ((__packed__)) vmcb {
 #define	SVM_CR3_LONG_RESERVED_MASK		0xfff0000000000fe7U
 #define	SVM_CR4_LEGACY_RESERVED_MASK		0xffbaf000U
 #define	SVM_CR4_RESERVED_MASK			0xffffffffffbaf000U
+#define	SVM_DR6_RESERVED_MASK			0xffffffffffff1ff0U
+#define	SVM_DR7_RESERVED_MASK			0xffffffff0000cc00U
+#define	SVM_EFER_RESERVED_MASK			0xffffffffffff0200U
 
 #define MSR_BITMAP_SIZE 8192
 
diff --git a/x86/svm_tests.c b/x86/svm_tests.c
index 99cfe4a..d96f3ee 100644
--- a/x86/svm_tests.c
+++ b/x86/svm_tests.c
@@ -1799,7 +1799,8 @@ static void basic_guest_main(struct svm_test *test)
 {
 }
 
-#define SVM_TEST_CR_RESERVED_BITS(start, end, inc, cr, val, resv_mask)	\
+#define SVM_TEST_REG_RESERVED_BITS(start, end, inc, str_name, reg, val,	\
+				   resv_mask)				\
 {									\
         u64 tmp, mask;							\
         int i;								\
@@ -1809,18 +1810,9 @@ static void basic_guest_main(struct svm_test *test)
                 if (!(mask & resv_mask))				\
                         continue;					\
                 tmp = val | mask;					\
-                switch (cr) {						\
-                        case 0:						\
-                                vmcb->save.cr0 = tmp;			\
-                                break;					\
-                        case 3:						\
-                                vmcb->save.cr3 = tmp;			\
-                                break;					\
-                        case 4:						\
-                                vmcb->save.cr4 = tmp;			\
-                }							\
-                report(svm_vmrun() == SVM_EXIT_ERR, "Test CR%d %d:%d: %lx",\
-		    cr, end, start, tmp);				\
+		reg = tmp;						\
+		report(svm_vmrun() == SVM_EXIT_ERR, "Test %s %d:%d: %lx",\
+		    str_name, end, start, tmp);				\
         }								\
 }
 
@@ -1871,7 +1863,7 @@ static void svm_guest_state_test(void)
 	 */
 	cr0 = cr0_saved;
 
-	SVM_TEST_CR_RESERVED_BITS(32, 63, 4, 0, cr0_saved,
+	SVM_TEST_REG_RESERVED_BITS(32, 63, 4, "CR0", vmcb->save.cr0, cr0_saved,
 	    SVM_CR0_RESERVED_MASK);
 	vmcb->save.cr0 = cr0_saved;
 
@@ -1891,19 +1883,19 @@ static void svm_guest_state_test(void)
 	vmcb->save.efer = efer;
 	cr4 |= X86_CR4_PAE;
 	vmcb->save.cr4 = cr4;
-	SVM_TEST_CR_RESERVED_BITS(0, 2, 1, 3, cr3_saved,
+	SVM_TEST_REG_RESERVED_BITS(0, 2, 1, "CR3", vmcb->save.cr3, cr3_saved,
 	    SVM_CR3_LEGACY_PAE_RESERVED_MASK);
 
 	cr4 = cr4_saved & ~X86_CR4_PAE;
 	vmcb->save.cr4 = cr4;
-	SVM_TEST_CR_RESERVED_BITS(0, 11, 2, 3, cr3_saved,
+	SVM_TEST_REG_RESERVED_BITS(0, 11, 2, "CR3", vmcb->save.cr3, cr3_saved,
 	    SVM_CR3_LEGACY_RESERVED_MASK);
 
 	cr4 |= X86_CR4_PAE;
 	vmcb->save.cr4 = cr4;
 	efer |= EFER_LMA;
 	vmcb->save.efer = efer;
-	SVM_TEST_CR_RESERVED_BITS(0, 63, 2, 3, cr3_saved,
+	SVM_TEST_REG_RESERVED_BITS(0, 63, 2, "CR3", vmcb->save.cr3, cr3_saved,
 	    SVM_CR3_LONG_RESERVED_MASK);
 
 	vmcb->save.cr4 = cr4_saved;
@@ -1919,18 +1911,45 @@ static void svm_guest_state_test(void)
 	efer_saved = vmcb->save.efer;
 	efer &= ~EFER_LMA;
 	vmcb->save.efer = efer;
-	SVM_TEST_CR_RESERVED_BITS(12, 31, 2, 4, cr4_saved,
+	SVM_TEST_REG_RESERVED_BITS(12, 31, 2, "CR4", vmcb->save.cr4, cr4_saved,
 	    SVM_CR4_LEGACY_RESERVED_MASK);
 
 	efer |= EFER_LMA;
 	vmcb->save.efer = efer;
-	SVM_TEST_CR_RESERVED_BITS(12, 31, 2, 4, cr4_saved,
+	SVM_TEST_REG_RESERVED_BITS(12, 31, 2, "CR4", vmcb->save.cr4, cr4_saved,
 	    SVM_CR4_RESERVED_MASK);
-	SVM_TEST_CR_RESERVED_BITS(32, 63, 4, 4, cr4_saved,
+	SVM_TEST_REG_RESERVED_BITS(32, 63, 4, "CR4", vmcb->save.cr4, cr4_saved,
 	    SVM_CR4_RESERVED_MASK);
 
 	vmcb->save.cr4 = cr4_saved;
 	vmcb->save.efer = efer_saved;
+
+	/*
+	 * DR6[63:32] and DR7[63:32] are MBZ
+	 */
+	u64 dr_saved = vmcb->save.dr6;
+
+	SVM_TEST_REG_RESERVED_BITS(32, 63, 4, "DR6", vmcb->save.dr6, dr_saved,
+	    SVM_DR6_RESERVED_MASK);
+	vmcb->save.dr6 = dr_saved;
+
+	dr_saved = vmcb->save.dr7;
+	SVM_TEST_REG_RESERVED_BITS(32, 63, 4, "DR7", vmcb->save.dr7, dr_saved,
+	    SVM_DR7_RESERVED_MASK);
+
+	vmcb->save.dr7 = dr_saved;
+
+	/*
+	 * EFER MBZ bits: 63:16, 9
+	 */
+	efer_saved = vmcb->save.efer;
+
+	SVM_TEST_REG_RESERVED_BITS(8, 9, 1, "EFER", vmcb->save.efer,
+	    efer_saved, SVM_EFER_RESERVED_MASK);
+	SVM_TEST_REG_RESERVED_BITS(16, 63, 4, "EFER", vmcb->save.efer,
+	    efer_saved, SVM_EFER_RESERVED_MASK);
+
+	vmcb->save.efer = efer_saved;
 }
 
 struct svm_test svm_tests[] = {
-- 
1.8.3.1

[PATCH 4/4] kvm-unit-tests: x86: Remove duplicate instance of 'vmcb'

[Krish Sadhukhan]

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

diff --git a/x86/svm.c b/x86/svm.c
index 41685bf..f984a60 100644
--- a/x86/svm.c
+++ b/x86/svm.c
@@ -201,7 +201,6 @@ struct regs get_regs(void)
 #define LOAD_GPR_C      SAVE_GPR_C
 
 struct svm_test *v2_test;
-struct vmcb *vmcb;
 
 #define ASM_VMRUN_CMD                           \
                 "vmload %%rax\n\t"              \
-- 
1.8.3.1

Re: [PATCH 0/4] KVM: nSVM: Check reserved bits in DR6, DR7 and EFER on vmrun of nested guests

[Paolo Bonzini]

On 23/05/20 00:19, Krish Sadhukhan wrote:
> Patch# 1: Moves the check for upper 32 reserved bits of DR6 to a new function.
> Patch# 2: Adds the KVM checks for DR6[63:32] and DR7[64:32] reserved bits
> Patch# 3: Adds kvm-unit-tests for DR6[63:32] and DR7[64:32] reserved bits and
> 	  reserved bits in EFER
> Patch# 4: Removes the duplicate definition of 'vmcb' that sneaked via one of
> 	  my previous patches.
> 
> 
> [PATCH 1/4] KVM: x86: Move the check for upper 32 reserved bits of
> [PATCH 2/4] KVM: nSVM: Check that DR6[63:32] and DR7[64:32] are not
> [PATCH 3/4] kvm-unit-tests: nSVM: Test that DR6[63:32], DR7[63:32]
> [PATCH 4/4] kvm-unit-tests: x86: Remove duplicate instance of 'vmcb'
> 
>  arch/x86/kvm/svm/nested.c | 3 +++
>  arch/x86/kvm/x86.c        | 2 +-
>  arch/x86/kvm/x86.h        | 5 +++++
>  3 files changed, 9 insertions(+), 1 deletion(-)
> 
> Krish Sadhukhan (2):
>       KVM: x86: Move the check for upper 32 reserved bits of DR6 to separate fun
>       KVM: nVMX: Check that DR6[63:32] and DR7[64:32] are not set on vmrun of ne
>  x86/svm.c       |  1 -
>  x86/svm.h       |  3 +++
>  x86/svm_tests.c | 59 ++++++++++++++++++++++++++++++++++++++-------------------
>  3 files changed, 42 insertions(+), 21 deletions(-)
> 
> Krish Sadhukhan (2):
>       kvm-unit-tests: nSVM: Test that DR6[63:32], DR7[63:32] and EFER reserved b
>       kvm-unit-tests: x86: Remove duplicate instance of 'vmcb'
> 

Queued, thanks.

Paolo

Re: [PATCH 0/4] KVM: nSVM: Check reserved bits in DR6, DR7 and EFER on vmrun of nested guests

[Krish Sadhukhan]

Ping.

On 5/22/20 3:19 PM, Krish Sadhukhan wrote:
> Patch# 1: Moves the check for upper 32 reserved bits of DR6 to a new function.
> Patch# 2: Adds the KVM checks for DR6[63:32] and DR7[64:32] reserved bits
> Patch# 3: Adds kvm-unit-tests for DR6[63:32] and DR7[64:32] reserved bits and
> 	  reserved bits in EFER
> Patch# 4: Removes the duplicate definition of 'vmcb' that sneaked via one of
> 	  my previous patches.
>
>
> [PATCH 1/4] KVM: x86: Move the check for upper 32 reserved bits of
> [PATCH 2/4] KVM: nSVM: Check that DR6[63:32] and DR7[64:32] are not
> [PATCH 3/4] kvm-unit-tests: nSVM: Test that DR6[63:32], DR7[63:32]
> [PATCH 4/4] kvm-unit-tests: x86: Remove duplicate instance of 'vmcb'
>
>   arch/x86/kvm/svm/nested.c | 3 +++
>   arch/x86/kvm/x86.c        | 2 +-
>   arch/x86/kvm/x86.h        | 5 +++++
>   3 files changed, 9 insertions(+), 1 deletion(-)
>
> Krish Sadhukhan (2):
>        KVM: x86: Move the check for upper 32 reserved bits of DR6 to separate fun
>        KVM: nVMX: Check that DR6[63:32] and DR7[64:32] are not set on vmrun of ne
>   x86/svm.c       |  1 -
>   x86/svm.h       |  3 +++
>   x86/svm_tests.c | 59 ++++++++++++++++++++++++++++++++++++++-------------------
>   3 files changed, 42 insertions(+), 21 deletions(-)
>
> Krish Sadhukhan (2):
>        kvm-unit-tests: nSVM: Test that DR6[63:32], DR7[63:32] and EFER reserved b
>        kvm-unit-tests: x86: Remove duplicate instance of 'vmcb'
>

Re: [PATCH 0/4] KVM: nSVM: Check reserved bits in DR6, DR7 and EFER on vmrun of nested guests

[Paolo Bonzini]

On 03/07/20 00:33, Krish Sadhukhan wrote:
> Ping.
> 
> On 5/22/20 3:19 PM, Krish Sadhukhan wrote:
>> Patch# 1: Moves the check for upper 32 reserved bits of DR6 to a new
>> function.
>> Patch# 2: Adds the KVM checks for DR6[63:32] and DR7[64:32] reserved bits
>> Patch# 3: Adds kvm-unit-tests for DR6[63:32] and DR7[64:32] reserved
>> bits and
>>       reserved bits in EFER
>> Patch# 4: Removes the duplicate definition of 'vmcb' that sneaked via
>> one of
>>       my previous patches.
>>
>>
>> [PATCH 1/4] KVM: x86: Move the check for upper 32 reserved bits of
>> [PATCH 2/4] KVM: nSVM: Check that DR6[63:32] and DR7[64:32] are not
>> [PATCH 3/4] kvm-unit-tests: nSVM: Test that DR6[63:32], DR7[63:32]
>> [PATCH 4/4] kvm-unit-tests: x86: Remove duplicate instance of 'vmcb'
>>
>>   arch/x86/kvm/svm/nested.c | 3 +++
>>   arch/x86/kvm/x86.c        | 2 +-
>>   arch/x86/kvm/x86.h        | 5 +++++
>>   3 files changed, 9 insertions(+), 1 deletion(-)
>>
>> Krish Sadhukhan (2):
>>        KVM: x86: Move the check for upper 32 reserved bits of DR6 to
>> separate fun
>>        KVM: nVMX: Check that DR6[63:32] and DR7[64:32] are not set on
>> vmrun of ne
>>   x86/svm.c       |  1 -
>>   x86/svm.h       |  3 +++
>>   x86/svm_tests.c | 59
>> ++++++++++++++++++++++++++++++++++++++-------------------
>>   3 files changed, 42 insertions(+), 21 deletions(-)
>>
>> Krish Sadhukhan (2):
>>        kvm-unit-tests: nSVM: Test that DR6[63:32], DR7[63:32] and EFER
>> reserved b
>>        kvm-unit-tests: x86: Remove duplicate instance of 'vmcb'
>>
> 

Queued, thanks.

Paolo