diff mbox series

[v6,05/13] arm64: Don't trap host pointer auth use to EL2

Message ID 20181207183931.4285-6-kristina.martsenko@arm.com
State New
Headers show
Series None | expand

Commit Message

Kristina Martsenko Dec. 7, 2018, 6:39 p.m. UTC 
From: Mark Rutland <mark.rutland@arm.com>


To allow EL0 (and/or EL1) to use pointer authentication functionality,
we must ensure that pointer authentication instructions and accesses to
pointer authentication keys are not trapped to EL2.

This patch ensures that HCR_EL2 is configured appropriately when the
kernel is booted at EL2. For non-VHE kernels we set HCR_EL2.{API,APK},
ensuring that EL1 can access keys and permit EL0 use of instructions.
For VHE kernels host EL0 (TGE && E2H) is unaffected by these settings,
and it doesn't matter how we configure HCR_EL2.{API,APK}, so we don't
bother setting them.

This does not enable support for KVM guests, since KVM manages HCR_EL2
itself when running VMs.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>

Signed-off-by: Kristina Martsenko <kristina.martsenko@arm.com>

Acked-by: Christoffer Dall <christoffer.dall@arm.com>

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: kvmarm@lists.cs.columbia.edu
---
 arch/arm64/include/asm/kvm_arm.h | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

-- 
2.11.0

Comments

Richard Henderson Dec. 9, 2018, 2:54 p.m. UTC | #1 
On 12/7/18 12:39 PM, Kristina Martsenko wrote:
> From: Mark Rutland <mark.rutland@arm.com>

> 

> To allow EL0 (and/or EL1) to use pointer authentication functionality,

> we must ensure that pointer authentication instructions and accesses to

> pointer authentication keys are not trapped to EL2.

> 

> This patch ensures that HCR_EL2 is configured appropriately when the

> kernel is booted at EL2. For non-VHE kernels we set HCR_EL2.{API,APK},

> ensuring that EL1 can access keys and permit EL0 use of instructions.

> For VHE kernels host EL0 (TGE && E2H) is unaffected by these settings,

> and it doesn't matter how we configure HCR_EL2.{API,APK}, so we don't

> bother setting them.

> 

> This does not enable support for KVM guests, since KVM manages HCR_EL2

> itself when running VMs.

> 

> Signed-off-by: Mark Rutland <mark.rutland@arm.com>

> Signed-off-by: Kristina Martsenko <kristina.martsenko@arm.com>

> Acked-by: Christoffer Dall <christoffer.dall@arm.com>

> Cc: Catalin Marinas <catalin.marinas@arm.com>

> Cc: Marc Zyngier <marc.zyngier@arm.com>

> Cc: Will Deacon <will.deacon@arm.com>

> Cc: kvmarm@lists.cs.columbia.edu

> ---

>  arch/arm64/include/asm/kvm_arm.h | 4 +++-

>  1 file changed, 3 insertions(+), 1 deletion(-)


Reviewed-by: Richard Henderson <richard.henderson@linaro.org>



r~
diff mbox series

Patch

diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h
index c8825c5a8dd0..f9123fe8fcf3 100644
--- a/arch/arm64/include/asm/kvm_arm.h
+++ b/arch/arm64/include/asm/kvm_arm.h
@@ -24,6 +24,8 @@ 
 
 /* Hyp Configuration Register (HCR) bits */
 #define HCR_FWB		(UL(1) << 46)
+#define HCR_API		(UL(1) << 41)
+#define HCR_APK		(UL(1) << 40)
 #define HCR_TEA		(UL(1) << 37)
 #define HCR_TERR	(UL(1) << 36)
 #define HCR_TLOR	(UL(1) << 35)
@@ -87,7 +89,7 @@ 
 			 HCR_AMO | HCR_SWIO | HCR_TIDCP | HCR_RW | HCR_TLOR | \
 			 HCR_FMO | HCR_IMO)
 #define HCR_VIRT_EXCP_MASK (HCR_VSE | HCR_VI | HCR_VF)
-#define HCR_HOST_NVHE_FLAGS (HCR_RW)
+#define HCR_HOST_NVHE_FLAGS (HCR_RW | HCR_API | HCR_APK)
 #define HCR_HOST_VHE_FLAGS (HCR_RW | HCR_TGE | HCR_E2H)
 
 /* TCR_EL2 Registers bits */