Re: [PATCH 1/4] KVM: arm64: Enable Pointer Authentication at EL2 if available
From: Mark Rutland <mark.rutland@arm.com>
Date: 2020-06-15 10:03:42
Also in:
kvm, kvmarm
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.
quoted hunk ↗ jump to hunk
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
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