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From: Mark Rutland <mark.rutland@arm.com>
To: linux-arm-kernel@lists.infradead.org
Cc: ardb@kernel.org, catalin.marinas@arm.com, james.morse@arm.com,
	joey.gouly@arm.com, mark.rutland@arm.com, maz@kernel.org,
	will@kernel.org
Subject: [PATCH 2/9] arm64: alternatives: kvm: prepare for cap changes
Date: Thu,  1 Sep 2022 16:13:56 +0100	[thread overview]
Message-ID: <20220901151403.1735836-3-mark.rutland@arm.com> (raw)
In-Reply-To: <20220901151403.1735836-1-mark.rutland@arm.com>

The KVM patching callbacks use cpus_have_final_cap() internally within
has_vhe(), and subsequent patches will make it invalid to call
cpus_have_final_cap() before alternatives patching has completed, and
will mean that cpus_have_const_cap() will always fall back to dynamic
checks prior to alternatives patching.

In preparation for said change, this patch modifies the KVM patching
callbacks to use cpus_have_cap() directly. This is not subject to
patching, and will dynamically check the cpu_hwcaps array, which is
functionally equivalent to the existing behaviour.

There should be no functional change as a result of this patch.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Joey Gouly <joey.gouly@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Will Deacon <will@kernel.org>
---
 arch/arm64/kvm/va_layout.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/kvm/va_layout.c b/arch/arm64/kvm/va_layout.c
index acdb7b3cc97d6..91b22a014610b 100644
--- a/arch/arm64/kvm/va_layout.c
+++ b/arch/arm64/kvm/va_layout.c
@@ -169,7 +169,7 @@ void __init kvm_update_va_mask(struct alt_instr *alt,
 		 * dictates it and we don't have any spare bits in the
 		 * address), NOP everything after masking the kernel VA.
 		 */
-		if (has_vhe() || (!tag_val && i > 0)) {
+		if (cpus_have_cap(ARM64_HAS_VIRT_HOST_EXTN) || (!tag_val && i > 0)) {
 			updptr[i] = cpu_to_le32(aarch64_insn_gen_nop());
 			continue;
 		}
@@ -193,7 +193,8 @@ void kvm_patch_vector_branch(struct alt_instr *alt,
 
 	BUG_ON(nr_inst != 4);
 
-	if (!cpus_have_const_cap(ARM64_SPECTRE_V3A) || WARN_ON_ONCE(has_vhe()))
+	if (!cpus_have_cap(ARM64_SPECTRE_V3A) ||
+	    WARN_ON_ONCE(cpus_have_cap(ARM64_HAS_VIRT_HOST_EXTN)))
 		return;
 
 	/*
-- 
2.30.2


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  parent reply	other threads:[~2022-09-01 15:15 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-01 15:13 [PATCH 0/9] arm64: alternatives: improvements Mark Rutland
2022-09-01 15:13 ` [PATCH 1/9] arm64: cpufeature: make cpus_have_cap() noinstr-safe Mark Rutland
2022-09-01 15:13 ` Mark Rutland [this message]
2022-09-01 15:13 ` [PATCH 3/9] arm64: alternatives: proton-pack: prepare for cap changes Mark Rutland
2022-09-02 16:19   ` Joey Gouly
2022-09-05  8:46     ` Mark Rutland
2022-09-01 15:13 ` [PATCH 4/9] arm64: alternatives: hoist print out of __apply_alternatives() Mark Rutland
2022-09-01 15:13 ` [PATCH 5/9] arm64: alternatives: make alt_region const Mark Rutland
2022-09-06 15:18   ` Ard Biesheuvel
2022-09-12  9:31     ` Mark Rutland
2022-09-12 10:13       ` Ard Biesheuvel
2022-09-12 12:13         ` Mark Rutland
2022-09-01 15:14 ` [PATCH 6/9] arm64: alternatives: have callbacks take a cap Mark Rutland
2022-09-02 15:54   ` Joey Gouly
2022-09-05  8:48     ` Mark Rutland
2022-09-01 15:14 ` [PATCH 7/9] arm64: alternatives: add alternative_has_feature_*() Mark Rutland
2022-09-01 15:14 ` [PATCH 8/9] arm64: alternatives: add shared NOP callback Mark Rutland
2022-09-01 15:14 ` [PATCH 9/9] HACK: arm64: alternatives: dump summary of alternatives Mark Rutland
2022-09-12 12:36   ` Mark Brown
2022-09-12 16:14     ` Mark Rutland

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