| Message ID | 20200615081954.6233-2-maz@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM/arm64: Enable PtrAuth on non-VHE KVM | expand |
On Mon, Jun 15, 2020 at 09:19:51AM +0100, Marc Zyngier wrote: > While initializing EL2, switch Pointer Authentication if detected ^ nit: on? > from EL1. We use the EL1-provided keys though. > > Signed-off-by: Marc Zyngier <maz@kernel.org> > --- > arch/arm64/kvm/hyp-init.S | 11 +++++++++++ > 1 file changed, 11 insertions(+) > > diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S > index 6e6ed5581eed..81732177507d 100644 > --- a/arch/arm64/kvm/hyp-init.S > +++ b/arch/arm64/kvm/hyp-init.S > @@ -104,6 +104,17 @@ alternative_else_nop_endif > */ > mov_q x4, (SCTLR_EL2_RES1 | (SCTLR_ELx_FLAGS & ~SCTLR_ELx_A)) > CPU_BE( orr x4, x4, #SCTLR_ELx_EE) > +alternative_if ARM64_HAS_ADDRESS_AUTH_ARCH > + b 1f > +alternative_else_nop_endif > +alternative_if_not ARM64_HAS_ADDRESS_AUTH_IMP_DEF > + b 2f > +alternative_else_nop_endif > +1: > + orr x4, x4, #(SCTLR_ELx_ENIA | SCTLR_ELx_ENIB) > + orr x4, x4, #SCTLR_ELx_ENDA > + orr x4, x4, #SCTLR_ELx_ENDB mm/proc.S builds the mask with ldr and ors it in one go, would be nice to use the same pattern. > +2: > msr sctlr_el2, x4 > isb Acked-by: Andrew Scull <ascull@google.com>
On Mon, Jun 15, 2020 at 09:19:51AM +0100, Marc Zyngier wrote: > While initializing EL2, switch Pointer Authentication if detected > from EL1. We use the EL1-provided keys though. Perhaps "enable address authentication", to avoid confusion with context-switch, and since generic authentication cannot be disabled locally at EL2. > > Signed-off-by: Marc Zyngier <maz@kernel.org> > --- > arch/arm64/kvm/hyp-init.S | 11 +++++++++++ > 1 file changed, 11 insertions(+) > > diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S > index 6e6ed5581eed..81732177507d 100644 > --- a/arch/arm64/kvm/hyp-init.S > +++ b/arch/arm64/kvm/hyp-init.S > @@ -104,6 +104,17 @@ alternative_else_nop_endif > */ > mov_q x4, (SCTLR_EL2_RES1 | (SCTLR_ELx_FLAGS & ~SCTLR_ELx_A)) > CPU_BE( orr x4, x4, #SCTLR_ELx_EE) > +alternative_if ARM64_HAS_ADDRESS_AUTH_ARCH > + b 1f > +alternative_else_nop_endif > +alternative_if_not ARM64_HAS_ADDRESS_AUTH_IMP_DEF > + b 2f > +alternative_else_nop_endif I see this is the same pattern we use in the kvm context switch, but I think we can use the ARM64_HAS_ADDRESS_AUTH cap instead (likewise in the existing code). AFAICT that won't permit mismatch given both ARM64_HAS_ADDRESS_AUTH_ARCH and ARM64_HAS_ADDRESS_AUTH_IMP_DEF are dealt with as ARM64_CPUCAP_BOOT_CPU_FEATURE. > +1: > + orr x4, x4, #(SCTLR_ELx_ENIA | SCTLR_ELx_ENIB) > + orr x4, x4, #SCTLR_ELx_ENDA > + orr x4, x4, #SCTLR_ELx_ENDB Assuming we have a spare register, it would be nice if we could follow the same pattern as in proc.S, where we do: | ldr x2, =SCTLR_ELx_ENIA | SCTLR_ELx_ENIB | \ | SCTLR_ELx_ENDA | SCTLR_ELx_ENDB | orr x0, x0, x2 ... though we could/should use mov_q rather than a load literal, here and in proc.S. ... otherwise this looks sound to me. Thanks, Mark. > +2: > msr sctlr_el2, x4 > isb > > -- > 2.27.0 > > _______________________________________________ > kvmarm mailing list > kvmarm@lists.cs.columbia.edu > https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
Hi Andrew, On 2020-06-15 09:48, Andrew Scull wrote: > On Mon, Jun 15, 2020 at 09:19:51AM +0100, Marc Zyngier wrote: >> While initializing EL2, switch Pointer Authentication if detected > > ^ nit: on? Yes. > >> from EL1. We use the EL1-provided keys though. >> >> Signed-off-by: Marc Zyngier <maz@kernel.org> >> --- >> arch/arm64/kvm/hyp-init.S | 11 +++++++++++ >> 1 file changed, 11 insertions(+) >> >> diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S >> index 6e6ed5581eed..81732177507d 100644 >> --- a/arch/arm64/kvm/hyp-init.S >> +++ b/arch/arm64/kvm/hyp-init.S >> @@ -104,6 +104,17 @@ alternative_else_nop_endif >> */ >> mov_q x4, (SCTLR_EL2_RES1 | (SCTLR_ELx_FLAGS & ~SCTLR_ELx_A)) >> CPU_BE( orr x4, x4, #SCTLR_ELx_EE) >> +alternative_if ARM64_HAS_ADDRESS_AUTH_ARCH >> + b 1f >> +alternative_else_nop_endif >> +alternative_if_not ARM64_HAS_ADDRESS_AUTH_IMP_DEF >> + b 2f >> +alternative_else_nop_endif >> +1: >> + orr x4, x4, #(SCTLR_ELx_ENIA | SCTLR_ELx_ENIB) >> + orr x4, x4, #SCTLR_ELx_ENDA >> + orr x4, x4, #SCTLR_ELx_ENDB > > mm/proc.S builds the mask with ldr and ors it in one go, would be nice > to use the same pattern. Do you actually mean kernel/head.S, or even __ptrauth_keys_init_cpu in asm/asm_pointer_auth.h? If so, I agree that it'd be good to make it look similar by using the mov_q macro, at the expense of a spare register (which we definitely can afford here). Thanks, M.
On 2020-06-15 11:03, Mark Rutland wrote: > On Mon, Jun 15, 2020 at 09:19:51AM +0100, Marc Zyngier wrote: >> While initializing EL2, switch Pointer Authentication if detected >> from EL1. We use the EL1-provided keys though. > > Perhaps "enable address authentication", to avoid confusion with > context-switch, and since generic authentication cannot be disabled > locally at EL2. Ah, fair enough. >> >> Signed-off-by: Marc Zyngier <maz@kernel.org> >> --- >> arch/arm64/kvm/hyp-init.S | 11 +++++++++++ >> 1 file changed, 11 insertions(+) >> >> diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S >> index 6e6ed5581eed..81732177507d 100644 >> --- a/arch/arm64/kvm/hyp-init.S >> +++ b/arch/arm64/kvm/hyp-init.S >> @@ -104,6 +104,17 @@ alternative_else_nop_endif >> */ >> mov_q x4, (SCTLR_EL2_RES1 | (SCTLR_ELx_FLAGS & ~SCTLR_ELx_A)) >> CPU_BE( orr x4, x4, #SCTLR_ELx_EE) >> +alternative_if ARM64_HAS_ADDRESS_AUTH_ARCH >> + b 1f >> +alternative_else_nop_endif >> +alternative_if_not ARM64_HAS_ADDRESS_AUTH_IMP_DEF >> + b 2f >> +alternative_else_nop_endif > > I see this is the same pattern we use in the kvm context switch, but I > think we can use the ARM64_HAS_ADDRESS_AUTH cap instead (likewise in > the > existing code). > > AFAICT that won't permit mismatch given both > ARM64_HAS_ADDRESS_AUTH_ARCH > and ARM64_HAS_ADDRESS_AUTH_IMP_DEF are dealt with as > ARM64_CPUCAP_BOOT_CPU_FEATURE. That'd be a nice cleanup, as the two back to back alternatives are a bit hard to read. > >> +1: >> + orr x4, x4, #(SCTLR_ELx_ENIA | SCTLR_ELx_ENIB) >> + orr x4, x4, #SCTLR_ELx_ENDA >> + orr x4, x4, #SCTLR_ELx_ENDB > > Assuming we have a spare register, it would be nice if we could follow > the same > pattern as in proc.S, where we do: > > | ldr x2, =SCTLR_ELx_ENIA | SCTLR_ELx_ENIB | \ > | SCTLR_ELx_ENDA | SCTLR_ELx_ENDB > | orr x0, x0, x2 > > ... though we could/should use mov_q rather than a load literal, here > and in > proc.S. Looks like this code isn't in -rc1 anymore, replaced with a mov_q in __ptrauth_keys_init_cpu. I'll switch to that in v2. Thanks, M.
diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S index 6e6ed5581eed..81732177507d 100644 --- a/arch/arm64/kvm/hyp-init.S +++ b/arch/arm64/kvm/hyp-init.S @@ -104,6 +104,17 @@ alternative_else_nop_endif */ mov_q x4, (SCTLR_EL2_RES1 | (SCTLR_ELx_FLAGS & ~SCTLR_ELx_A)) CPU_BE( orr x4, x4, #SCTLR_ELx_EE) +alternative_if ARM64_HAS_ADDRESS_AUTH_ARCH + b 1f +alternative_else_nop_endif +alternative_if_not ARM64_HAS_ADDRESS_AUTH_IMP_DEF + b 2f +alternative_else_nop_endif +1: + orr x4, x4, #(SCTLR_ELx_ENIA | SCTLR_ELx_ENIB) + orr x4, x4, #SCTLR_ELx_ENDA + orr x4, x4, #SCTLR_ELx_ENDB +2: msr sctlr_el2, x4 isb
While initializing EL2, switch Pointer Authentication if detected from EL1. We use the EL1-provided keys though. Signed-off-by: Marc Zyngier <maz@kernel.org> --- arch/arm64/kvm/hyp-init.S | 11 +++++++++++ 1 file changed, 11 insertions(+)