[PATCH v2 05/11] arm64: sve: Provide a conditional update accessor for ZCR_ELx

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From: Marc Zyngier <maz@kernel.org>
To: kvmarm@lists.cs.columbia.edu,
	linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org
Cc: kernel-team@android.com,
	Catalin Marinas <catalin.marinas@arm.com>,
	broonie@kernel.org, Will Deacon <will@kernel.org>,
	dave.martin@arm.com, daniel.kiss@arm.com
Subject: [PATCH v2 05/11] arm64: sve: Provide a conditional update accessor for ZCR_ELx
Date: Thu, 18 Mar 2021 12:25:26 +0000	[thread overview]
Message-ID: <20210318122532.505263-6-maz@kernel.org> (raw)
In-Reply-To: <20210318122532.505263-1-maz@kernel.org>

A common pattern is to conditionally update ZCR_ELx in order
to avoid the "self-synchronizing" effect that writing to this
register has.

Let's provide an accessor that does exactly this.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/include/asm/fpsimd.h | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/arch/arm64/include/asm/fpsimd.h b/arch/arm64/include/asm/fpsimd.h
index bec5f14b622a..05c9c55768b8 100644
--- a/arch/arm64/include/asm/fpsimd.h
+++ b/arch/arm64/include/asm/fpsimd.h
@@ -130,6 +130,15 @@ static inline void sve_user_enable(void)
 	sysreg_clear_set(cpacr_el1, 0, CPACR_EL1_ZEN_EL0EN);
 }
 
+#define sve_cond_update_zcr_vq(val, reg)		\
+	do {						\
+		u64 __zcr = read_sysreg_s((reg));	\
+		u64 __new = __zcr & ~ZCR_ELx_LEN_MASK;	\
+		__new |= (val) & ZCR_ELx_LEN_MASK;	\
+		if (__zcr != __new)			\
+			write_sysreg_s(__new, (reg));	\
+	} while (0)
+
 /*
  * Probing and setup functions.
  * Calls to these functions must be serialised with one another.
-- 
2.29.2

_______________________________________________
kvmarm mailing list
kvmarm@lists.cs.columbia.edu
https://lists.cs.columbia.edu/mailman/listinfo/kvmarm

WARNING: multiple messages have this Message-ID (diff)

From: Marc Zyngier <maz@kernel.org>
To: kvmarm@lists.cs.columbia.edu,
	linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org
Cc: dave.martin@arm.com, daniel.kiss@arm.com,
	Will Deacon <will@kernel.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	James Morse <james.morse@arm.com>,
	Julien Thierry <julien.thierry.kdev@gmail.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	broonie@kernel.org, ascull@google.com, qperret@google.com,
	kernel-team@android.com
Subject: [PATCH v2 05/11] arm64: sve: Provide a conditional update accessor for ZCR_ELx
Date: Thu, 18 Mar 2021 12:25:26 +0000	[thread overview]
Message-ID: <20210318122532.505263-6-maz@kernel.org> (raw)
In-Reply-To: <20210318122532.505263-1-maz@kernel.org>

A common pattern is to conditionally update ZCR_ELx in order
to avoid the "self-synchronizing" effect that writing to this
register has.

Let's provide an accessor that does exactly this.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/include/asm/fpsimd.h | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/arch/arm64/include/asm/fpsimd.h b/arch/arm64/include/asm/fpsimd.h
index bec5f14b622a..05c9c55768b8 100644
--- a/arch/arm64/include/asm/fpsimd.h
+++ b/arch/arm64/include/asm/fpsimd.h
@@ -130,6 +130,15 @@ static inline void sve_user_enable(void)
 	sysreg_clear_set(cpacr_el1, 0, CPACR_EL1_ZEN_EL0EN);
 }
 
+#define sve_cond_update_zcr_vq(val, reg)		\
+	do {						\
+		u64 __zcr = read_sysreg_s((reg));	\
+		u64 __new = __zcr & ~ZCR_ELx_LEN_MASK;	\
+		__new |= (val) & ZCR_ELx_LEN_MASK;	\
+		if (__zcr != __new)			\
+			write_sysreg_s(__new, (reg));	\
+	} while (0)
+
 /*
  * Probing and setup functions.
  * Calls to these functions must be serialised with one another.
-- 
2.29.2


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

WARNING: multiple messages have this Message-ID (diff)

From: Marc Zyngier <maz@kernel.org>
To: kvmarm@lists.cs.columbia.edu,
	linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org
Cc: dave.martin@arm.com, daniel.kiss@arm.com,
	Will Deacon <will@kernel.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	James Morse <james.morse@arm.com>,
	Julien Thierry <julien.thierry.kdev@gmail.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	broonie@kernel.org, ascull@google.com, qperret@google.com,
	kernel-team@android.com
Subject: [PATCH v2 05/11] arm64: sve: Provide a conditional update accessor for ZCR_ELx
Date: Thu, 18 Mar 2021 12:25:26 +0000	[thread overview]
Message-ID: <20210318122532.505263-6-maz@kernel.org> (raw)
In-Reply-To: <20210318122532.505263-1-maz@kernel.org>

A common pattern is to conditionally update ZCR_ELx in order
to avoid the "self-synchronizing" effect that writing to this
register has.

Let's provide an accessor that does exactly this.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/include/asm/fpsimd.h | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/arch/arm64/include/asm/fpsimd.h b/arch/arm64/include/asm/fpsimd.h
index bec5f14b622a..05c9c55768b8 100644
--- a/arch/arm64/include/asm/fpsimd.h
+++ b/arch/arm64/include/asm/fpsimd.h
@@ -130,6 +130,15 @@ static inline void sve_user_enable(void)
 	sysreg_clear_set(cpacr_el1, 0, CPACR_EL1_ZEN_EL0EN);
 }
 
+#define sve_cond_update_zcr_vq(val, reg)		\
+	do {						\
+		u64 __zcr = read_sysreg_s((reg));	\
+		u64 __new = __zcr & ~ZCR_ELx_LEN_MASK;	\
+		__new |= (val) & ZCR_ELx_LEN_MASK;	\
+		if (__zcr != __new)			\
+			write_sysreg_s(__new, (reg));	\
+	} while (0)
+
 /*
  * Probing and setup functions.
  * Calls to these functions must be serialised with one another.
-- 
2.29.2

next prev parent reply	other threads:[~2021-03-18 12:25 UTC|newest]

Thread overview: 72+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-18 12:25 [PATCH v2 00/11] KVM: arm64: Enable SVE support on nVHE systems Marc Zyngier
2021-03-18 12:25 ` Marc Zyngier
2021-03-18 12:25 ` Marc Zyngier
2021-03-18 12:25 ` [PATCH v2 01/11] KVM: arm64: Provide KVM's own save/restore SVE primitives Marc Zyngier
2021-03-18 12:25   ` Marc Zyngier
2021-03-18 12:25   ` Marc Zyngier
2021-03-18 12:25 ` [PATCH v2 02/11] KVM: arm64: Use {read, write}_sysreg_el1 to access ZCR_EL1 Marc Zyngier
2021-03-18 12:25   ` [PATCH v2 02/11] KVM: arm64: Use {read,write}_sysreg_el1 " Marc Zyngier
2021-03-18 12:25   ` [PATCH v2 02/11] KVM: arm64: Use {read, write}_sysreg_el1 " Marc Zyngier
2021-03-18 12:25 ` [PATCH v2 03/11] KVM: arm64: Let vcpu_sve_pffr() handle HYP VAs Marc Zyngier
2021-03-18 12:25   ` Marc Zyngier
2021-03-18 12:25   ` Marc Zyngier
2021-03-18 12:25 ` [PATCH v2 04/11] KVM: arm64: Introduce vcpu_sve_vq() helper Marc Zyngier
2021-03-18 12:25   ` Marc Zyngier
2021-03-18 12:25   ` Marc Zyngier
2021-03-18 12:25 ` Marc Zyngier [this message]
2021-03-18 12:25   ` [PATCH v2 05/11] arm64: sve: Provide a conditional update accessor for ZCR_ELx Marc Zyngier
2021-03-18 12:25   ` Marc Zyngier
2021-03-18 13:32   ` Will Deacon
2021-03-18 13:32     ` Will Deacon
2021-03-18 13:32     ` Will Deacon
2021-03-19 16:42   ` Mark Brown
2021-03-19 16:42     ` Mark Brown
2021-03-19 16:42     ` Mark Brown
2021-03-19 16:51     ` Marc Zyngier
2021-03-19 16:51       ` Marc Zyngier
2021-03-19 16:51       ` Marc Zyngier
2021-03-19 16:58       ` Mark Brown
2021-03-19 16:58         ` Mark Brown
2021-03-19 16:58         ` Mark Brown
2021-03-18 12:25 ` [PATCH v2 06/11] KVM: arm64: Rework SVE host-save/guest-restore Marc Zyngier
2021-03-18 12:25   ` Marc Zyngier
2021-03-18 12:25   ` Marc Zyngier
2021-03-18 13:34   ` Will Deacon
2021-03-18 13:34     ` Will Deacon
2021-03-18 13:34     ` Will Deacon
2021-03-18 12:25 ` [PATCH v2 07/11] KVM: arm64: Map SVE context at EL2 when available Marc Zyngier
2021-03-18 12:25   ` Marc Zyngier
2021-03-18 12:25   ` Marc Zyngier
2021-03-18 13:35   ` Will Deacon
2021-03-18 13:35     ` Will Deacon
2021-03-18 13:35     ` Will Deacon
2021-03-18 12:25 ` [PATCH v2 08/11] KVM: arm64: Save guest's ZCR_EL1 before saving the FPSIMD state Marc Zyngier
2021-03-18 12:25   ` Marc Zyngier
2021-03-18 12:25   ` Marc Zyngier
2021-03-18 12:25 ` [PATCH v2 09/11] KVM: arm64: Trap host SVE accesses when the FPSIMD state is dirty Marc Zyngier
2021-03-18 12:25   ` Marc Zyngier
2021-03-18 12:25   ` Marc Zyngier
2021-03-18 14:11   ` Will Deacon
2021-03-18 14:11     ` Will Deacon
2021-03-18 14:11     ` Will Deacon
2021-03-18 14:29     ` Marc Zyngier
2021-03-18 14:29       ` Marc Zyngier
2021-03-18 14:29       ` Marc Zyngier
2021-03-18 18:40   ` Marc Zyngier
2021-03-18 18:40     ` Marc Zyngier
2021-03-18 18:40     ` Marc Zyngier
2021-03-18 12:25 ` [PATCH v2 10/11] KVM: arm64: Save/restore SVE state for nVHE Marc Zyngier
2021-03-18 12:25   ` Marc Zyngier
2021-03-18 12:25   ` Marc Zyngier
2021-03-18 14:13   ` Will Deacon
2021-03-18 14:13     ` Will Deacon
2021-03-18 14:13     ` Will Deacon
2021-03-18 14:32     ` Marc Zyngier
2021-03-18 14:32       ` Marc Zyngier
2021-03-18 14:32       ` Marc Zyngier
2021-03-18 12:25 ` [PATCH v2 11/11] KVM: arm64: Enable SVE support " Marc Zyngier
2021-03-18 12:25   ` Marc Zyngier
2021-03-18 12:25   ` Marc Zyngier
2021-03-19 17:53 ` [PATCH v2 00/11] KVM: arm64: Enable SVE support on nVHE systems Mark Brown
2021-03-19 17:53   ` Mark Brown
2021-03-19 17:53   ` Mark Brown

find likely ancestor, descendant, or conflicting patches for this message:
( dfblob:bec5f14b622 dfblob:05c9c55768b dfblob:bec5f14b622
dfblob:05c9c55768b dfblob:bec5f14b622 dfblob:05c9c55768b )
 OR (
bs:"[PATCH v2 05/11] arm64: sve: Provide a conditional update accessor for ZCR_ELx" )
	(help)

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