diff mbox

[RFC,v2,18/20] x86/kvm: Enable Secure Memory Encryption of nested page tables

Message ID 20160822223849.29880.35462.stgit@tlendack-t1.amdoffice.net (mailing list archive)
State New, archived
Headers show

Commit Message

Tom Lendacky Aug. 22, 2016, 10:38 p.m. UTC 
Update the KVM support to include the memory encryption mask when creating
and using nested page tables.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
---
 arch/x86/include/asm/kvm_host.h |    3 ++-
 arch/x86/kvm/mmu.c              |    8 ++++++--
 arch/x86/kvm/vmx.c              |    3 ++-
 arch/x86/kvm/x86.c              |    3 ++-
 4 files changed, 12 insertions(+), 5 deletions(-)


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Comments

Borislav Petkov Sept. 12, 2016, 2:35 p.m. UTC | #1 
On Mon, Aug 22, 2016 at 05:38:49PM -0500, Tom Lendacky wrote:
> Update the KVM support to include the memory encryption mask when creating
> and using nested page tables.
> 
> Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
> ---
>  arch/x86/include/asm/kvm_host.h |    3 ++-
>  arch/x86/kvm/mmu.c              |    8 ++++++--
>  arch/x86/kvm/vmx.c              |    3 ++-
>  arch/x86/kvm/x86.c              |    3 ++-
>  4 files changed, 12 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
> index 33ae3a4..c51c1cb 100644
> --- a/arch/x86/include/asm/kvm_host.h
> +++ b/arch/x86/include/asm/kvm_host.h
> @@ -1039,7 +1039,8 @@ void kvm_mmu_setup(struct kvm_vcpu *vcpu);
>  void kvm_mmu_init_vm(struct kvm *kvm);
>  void kvm_mmu_uninit_vm(struct kvm *kvm);
>  void kvm_mmu_set_mask_ptes(u64 user_mask, u64 accessed_mask,
> -		u64 dirty_mask, u64 nx_mask, u64 x_mask, u64 p_mask);
> +		u64 dirty_mask, u64 nx_mask, u64 x_mask, u64 p_mask,
> +		u64 me_mask);

Why do you need a separate mask?

arch/x86/kvm/mmu.c::set_spte() ORs in shadow_present_mask
unconditionally. So you can simply do:


	kvm_mmu_set_mask_ptes(PT_USER_MASK, PT_ACCESSED_MASK,
			      PT_DIRTY_MASK, PT64_NX_MASK, 0,
			      PT_PRESENT_MASK | sme_me_mask);

and have this change much simpler.

>  void kvm_mmu_reset_context(struct kvm_vcpu *vcpu);
>  void kvm_mmu_slot_remove_write_access(struct kvm *kvm,
> diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
> index 3d4cc8cc..a7040f4 100644
> --- a/arch/x86/kvm/mmu.c
> +++ b/arch/x86/kvm/mmu.c
> @@ -122,7 +122,7 @@ module_param(dbg, bool, 0644);
>  					    * PT32_LEVEL_BITS))) - 1))
>  
>  #define PT64_PERM_MASK (PT_PRESENT_MASK | PT_WRITABLE_MASK | shadow_user_mask \
> -			| shadow_x_mask | shadow_nx_mask)
> +			| shadow_x_mask | shadow_nx_mask | shadow_me_mask)

This would be sme_me_mask, of course, like with the baremetal masks.

Or am I missing something?
Tom Lendacky Sept. 14, 2016, 2:02 p.m. UTC | #2 
On 09/12/2016 09:35 AM, Borislav Petkov wrote:
> On Mon, Aug 22, 2016 at 05:38:49PM -0500, Tom Lendacky wrote:
>> Update the KVM support to include the memory encryption mask when creating
>> and using nested page tables.
>>
>> Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
>> ---
>>  arch/x86/include/asm/kvm_host.h |    3 ++-
>>  arch/x86/kvm/mmu.c              |    8 ++++++--
>>  arch/x86/kvm/vmx.c              |    3 ++-
>>  arch/x86/kvm/x86.c              |    3 ++-
>>  4 files changed, 12 insertions(+), 5 deletions(-)
>>
>> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
>> index 33ae3a4..c51c1cb 100644
>> --- a/arch/x86/include/asm/kvm_host.h
>> +++ b/arch/x86/include/asm/kvm_host.h
>> @@ -1039,7 +1039,8 @@ void kvm_mmu_setup(struct kvm_vcpu *vcpu);
>>  void kvm_mmu_init_vm(struct kvm *kvm);
>>  void kvm_mmu_uninit_vm(struct kvm *kvm);
>>  void kvm_mmu_set_mask_ptes(u64 user_mask, u64 accessed_mask,
>> -		u64 dirty_mask, u64 nx_mask, u64 x_mask, u64 p_mask);
>> +		u64 dirty_mask, u64 nx_mask, u64 x_mask, u64 p_mask,
>> +		u64 me_mask);
> 
> Why do you need a separate mask?
> 
> arch/x86/kvm/mmu.c::set_spte() ORs in shadow_present_mask
> unconditionally. So you can simply do:
> 
> 
> 	kvm_mmu_set_mask_ptes(PT_USER_MASK, PT_ACCESSED_MASK,
> 			      PT_DIRTY_MASK, PT64_NX_MASK, 0,
> 			      PT_PRESENT_MASK | sme_me_mask);
> 
> and have this change much simpler.

Just keeping in step with the way this is done for the other masks.
They each have a specific meaning so I was trying not to combine
them in case they may be used differently in the future.

> 
>>  void kvm_mmu_reset_context(struct kvm_vcpu *vcpu);
>>  void kvm_mmu_slot_remove_write_access(struct kvm *kvm,
>> diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
>> index 3d4cc8cc..a7040f4 100644
>> --- a/arch/x86/kvm/mmu.c
>> +++ b/arch/x86/kvm/mmu.c
>> @@ -122,7 +122,7 @@ module_param(dbg, bool, 0644);
>>  					    * PT32_LEVEL_BITS))) - 1))
>>  
>>  #define PT64_PERM_MASK (PT_PRESENT_MASK | PT_WRITABLE_MASK | shadow_user_mask \
>> -			| shadow_x_mask | shadow_nx_mask)
>> +			| shadow_x_mask | shadow_nx_mask | shadow_me_mask)
> 
> This would be sme_me_mask, of course, like with the baremetal masks.
> 
> Or am I missing something?

Given the current patch, this would be shadow_me_mask since that value
is set by the call to kvm_mmu_set_mask_ptes.

Thanks,
Tom

> 
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diff mbox

Patch

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 33ae3a4..c51c1cb 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1039,7 +1039,8 @@  void kvm_mmu_setup(struct kvm_vcpu *vcpu);
 void kvm_mmu_init_vm(struct kvm *kvm);
 void kvm_mmu_uninit_vm(struct kvm *kvm);
 void kvm_mmu_set_mask_ptes(u64 user_mask, u64 accessed_mask,
-		u64 dirty_mask, u64 nx_mask, u64 x_mask, u64 p_mask);
+		u64 dirty_mask, u64 nx_mask, u64 x_mask, u64 p_mask,
+		u64 me_mask);
 
 void kvm_mmu_reset_context(struct kvm_vcpu *vcpu);
 void kvm_mmu_slot_remove_write_access(struct kvm *kvm,
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 3d4cc8cc..a7040f4 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -122,7 +122,7 @@  module_param(dbg, bool, 0644);
 					    * PT32_LEVEL_BITS))) - 1))
 
 #define PT64_PERM_MASK (PT_PRESENT_MASK | PT_WRITABLE_MASK | shadow_user_mask \
-			| shadow_x_mask | shadow_nx_mask)
+			| shadow_x_mask | shadow_nx_mask | shadow_me_mask)
 
 #define ACC_EXEC_MASK    1
 #define ACC_WRITE_MASK   PT_WRITABLE_MASK
@@ -177,6 +177,7 @@  static u64 __read_mostly shadow_accessed_mask;
 static u64 __read_mostly shadow_dirty_mask;
 static u64 __read_mostly shadow_mmio_mask;
 static u64 __read_mostly shadow_present_mask;
+static u64 __read_mostly shadow_me_mask;
 
 static void mmu_spte_set(u64 *sptep, u64 spte);
 static void mmu_free_roots(struct kvm_vcpu *vcpu);
@@ -284,7 +285,8 @@  static bool check_mmio_spte(struct kvm_vcpu *vcpu, u64 spte)
 }
 
 void kvm_mmu_set_mask_ptes(u64 user_mask, u64 accessed_mask,
-		u64 dirty_mask, u64 nx_mask, u64 x_mask, u64 p_mask)
+		u64 dirty_mask, u64 nx_mask, u64 x_mask, u64 p_mask,
+		u64 me_mask)
 {
 	shadow_user_mask = user_mask;
 	shadow_accessed_mask = accessed_mask;
@@ -292,6 +294,7 @@  void kvm_mmu_set_mask_ptes(u64 user_mask, u64 accessed_mask,
 	shadow_nx_mask = nx_mask;
 	shadow_x_mask = x_mask;
 	shadow_present_mask = p_mask;
+	shadow_me_mask = me_mask;
 }
 EXPORT_SYMBOL_GPL(kvm_mmu_set_mask_ptes);
 
@@ -2553,6 +2556,7 @@  static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
 		pte_access &= ~ACC_WRITE_MASK;
 
 	spte |= (u64)pfn << PAGE_SHIFT;
+	spte |= shadow_me_mask;
 
 	if (pte_access & ACC_WRITE_MASK) {
 
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 87eaa6b..9040645 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -6485,7 +6485,8 @@  static __init int hardware_setup(void)
 			(enable_ept_ad_bits) ? VMX_EPT_DIRTY_BIT : 0ull,
 			0ull, VMX_EPT_EXECUTABLE_MASK,
 			cpu_has_vmx_ept_execute_only() ?
-				      0ull : VMX_EPT_READABLE_MASK);
+				      0ull : VMX_EPT_READABLE_MASK,
+			0ull);
 		ept_set_mmio_spte_mask();
 		kvm_enable_tdp();
 	} else
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 19f9f9e..d432894 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -65,6 +65,7 @@ 
 #include <asm/pvclock.h>
 #include <asm/div64.h>
 #include <asm/irq_remapping.h>
+#include <asm/mem_encrypt.h>
 
 #define CREATE_TRACE_POINTS
 #include "trace.h"
@@ -5875,7 +5876,7 @@  int kvm_arch_init(void *opaque)
 
 	kvm_mmu_set_mask_ptes(PT_USER_MASK, PT_ACCESSED_MASK,
 			PT_DIRTY_MASK, PT64_NX_MASK, 0,
-			PT_PRESENT_MASK);
+			PT_PRESENT_MASK, sme_me_mask);
 	kvm_timer_init();
 
 	perf_register_guest_info_callbacks(&kvm_guest_cbs);