| Message ID | 20180417183735.56985-5-mark.rutland@arm.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | ARMv8.3 pointer authentication userspace support | expand |
On Tue, Apr 17, 2018 at 07:37:28PM +0100, Mark Rutland wrote: > 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> > Cc: Christoffer Dall <cdall@kernel.org> > 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 FWIW: Acked-by: Christoffer Dall <christoffer.dall@arm.com> > --- > arch/arm64/include/asm/kvm_arm.h | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h > index 89b3dda7e3cb..4d57e1e58323 100644 > --- a/arch/arm64/include/asm/kvm_arm.h > +++ b/arch/arm64/include/asm/kvm_arm.h > @@ -23,6 +23,8 @@ > #include <asm/types.h> > > /* Hyp Configuration Register (HCR) bits */ > +#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) > @@ -86,7 +88,7 @@ > 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 */ > -- > 2.11.0 > > _______________________________________________ > kvmarm mailing list > kvmarm@lists.cs.columbia.edu > https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h index 89b3dda7e3cb..4d57e1e58323 100644 --- a/arch/arm64/include/asm/kvm_arm.h +++ b/arch/arm64/include/asm/kvm_arm.h @@ -23,6 +23,8 @@ #include <asm/types.h> /* Hyp Configuration Register (HCR) bits */ +#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) @@ -86,7 +88,7 @@ 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 */
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> Cc: Christoffer Dall <cdall@kernel.org> 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