[PATCH v2 1/2] arm64: kvm: Save/restore MTE registers

From: Steven Price <steven.price@arm.com>
To: Catalin Marinas <catalin.marinas@arm.com>,
	Marc Zyngier <maz@kernel.org>, Will Deacon <will@kernel.org>
Cc: Steven Price <steven.price@arm.com>,
	James Morse <james.morse@arm.com>,
	Julien Thierry <julien.thierry.kdev@gmail.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	kvmarm@lists.cs.columbia.edu,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, Dave Martin <Dave.Martin@arm.com>,
	Mark Rutland <mark.rutland@arm.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	qemu-devel@nongnu.org, Juan Quintela <quintela@redhat.com>,
	"Dr. David Alan Gilbert" <dgilbert@redhat.com>,
	Richard Henderson <richard.henderson@linaro.org>,
	Peter Maydell <Peter.Maydell@arm.com>,
	Haibo Xu <Haibo.Xu@arm.com>
Subject: [PATCH v2 1/2] arm64: kvm: Save/restore MTE registers
Date: Fri,  4 Sep 2020 17:00:17 +0100	[thread overview]
Message-ID: <20200904160018.29481-2-steven.price@arm.com> (raw)
In-Reply-To: <20200904160018.29481-1-steven.price@arm.com>

Define the new system registers that MTE introduces and context switch
them. The MTE feature is still hidden from the ID register as it isn't
supported in a VM yet.

Signed-off-by: Steven Price <steven.price@arm.com>
---
 arch/arm64/include/asm/kvm_host.h          |  4 ++++
 arch/arm64/include/asm/sysreg.h            |  3 ++-
 arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h | 14 ++++++++++++++
 arch/arm64/kvm/sys_regs.c                  | 14 ++++++++++----
 4 files changed, 30 insertions(+), 5 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index e52c927aade5..4f4360dd149e 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -126,6 +126,8 @@ enum vcpu_sysreg {
 	SCTLR_EL1,	/* System Control Register */
 	ACTLR_EL1,	/* Auxiliary Control Register */
 	CPACR_EL1,	/* Coprocessor Access Control */
+	RGSR_EL1,	/* Random Allocation Tag Seed Register */
+	GCR_EL1,	/* Tag Control Register */
 	ZCR_EL1,	/* SVE Control */
 	TTBR0_EL1,	/* Translation Table Base Register 0 */
 	TTBR1_EL1,	/* Translation Table Base Register 1 */
@@ -142,6 +144,8 @@ enum vcpu_sysreg {
 	TPIDR_EL1,	/* Thread ID, Privileged */
 	AMAIR_EL1,	/* Aux Memory Attribute Indirection Register */
 	CNTKCTL_EL1,	/* Timer Control Register (EL1) */
+	TFSRE0_EL1,	/* Tag Fault Status Register (EL0) */
+	TFSR_EL1,	/* Tag Fault Stauts Register (EL1) */
 	PAR_EL1,	/* Physical Address Register */
 	MDSCR_EL1,	/* Monitor Debug System Control Register */
 	MDCCINT_EL1,	/* Monitor Debug Comms Channel Interrupt Enable Reg */
diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
index 52eefe2f7d95..cd60677551b7 100644
--- a/arch/arm64/include/asm/sysreg.h
+++ b/arch/arm64/include/asm/sysreg.h
@@ -563,7 +563,8 @@
 #define SCTLR_ELx_M	(BIT(0))
 
 #define SCTLR_ELx_FLAGS	(SCTLR_ELx_M  | SCTLR_ELx_A | SCTLR_ELx_C | \
-			 SCTLR_ELx_SA | SCTLR_ELx_I | SCTLR_ELx_IESB)
+			 SCTLR_ELx_SA | SCTLR_ELx_I | SCTLR_ELx_IESB | \
+			 SCTLR_ELx_ITFSB)
 
 /* SCTLR_EL2 specific flags. */
 #define SCTLR_EL2_RES1	((BIT(4))  | (BIT(5))  | (BIT(11)) | (BIT(16)) | \
diff --git a/arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h b/arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h
index 7a986030145f..a124ffa49ba3 100644
--- a/arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h
+++ b/arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h
@@ -18,6 +18,11 @@
 static inline void __sysreg_save_common_state(struct kvm_cpu_context *ctxt)
 {
 	ctxt_sys_reg(ctxt, MDSCR_EL1)	= read_sysreg(mdscr_el1);
+	if (system_supports_mte()) {
+		ctxt_sys_reg(ctxt, RGSR_EL1)	= read_sysreg_s(SYS_RGSR_EL1);
+		ctxt_sys_reg(ctxt, GCR_EL1)	= read_sysreg_s(SYS_GCR_EL1);
+		ctxt_sys_reg(ctxt, TFSRE0_EL1)	= read_sysreg_s(SYS_TFSRE0_EL1);
+	}
 }
 
 static inline void __sysreg_save_user_state(struct kvm_cpu_context *ctxt)
@@ -45,6 +50,8 @@ static inline void __sysreg_save_el1_state(struct kvm_cpu_context *ctxt)
 	ctxt_sys_reg(ctxt, CNTKCTL_EL1)	= read_sysreg_el1(SYS_CNTKCTL);
 	ctxt_sys_reg(ctxt, PAR_EL1)	= read_sysreg(par_el1);
 	ctxt_sys_reg(ctxt, TPIDR_EL1)	= read_sysreg(tpidr_el1);
+	if (system_supports_mte())
+		ctxt_sys_reg(ctxt, TFSR_EL1) = read_sysreg_el1(SYS_TFSR);
 
 	ctxt_sys_reg(ctxt, SP_EL1)	= read_sysreg(sp_el1);
 	ctxt_sys_reg(ctxt, ELR_EL1)	= read_sysreg_el1(SYS_ELR);
@@ -63,6 +70,11 @@ static inline void __sysreg_save_el2_return_state(struct kvm_cpu_context *ctxt)
 static inline void __sysreg_restore_common_state(struct kvm_cpu_context *ctxt)
 {
 	write_sysreg(ctxt_sys_reg(ctxt, MDSCR_EL1),  mdscr_el1);
+	if (system_supports_mte()) {
+		write_sysreg_s(ctxt_sys_reg(ctxt, RGSR_EL1), SYS_RGSR_EL1);
+		write_sysreg_s(ctxt_sys_reg(ctxt, GCR_EL1), SYS_GCR_EL1);
+		write_sysreg_s(ctxt_sys_reg(ctxt, TFSRE0_EL1), SYS_TFSRE0_EL1);
+	}
 }
 
 static inline void __sysreg_restore_user_state(struct kvm_cpu_context *ctxt)
@@ -106,6 +118,8 @@ static inline void __sysreg_restore_el1_state(struct kvm_cpu_context *ctxt)
 	write_sysreg_el1(ctxt_sys_reg(ctxt, CNTKCTL_EL1), SYS_CNTKCTL);
 	write_sysreg(ctxt_sys_reg(ctxt, PAR_EL1),	par_el1);
 	write_sysreg(ctxt_sys_reg(ctxt, TPIDR_EL1),	tpidr_el1);
+	if (system_supports_mte())
+		write_sysreg_el1(ctxt_sys_reg(ctxt, TFSR_EL1), SYS_TFSR);
 
 	if (!has_vhe() &&
 	    cpus_have_final_cap(ARM64_WORKAROUND_SPECULATIVE_AT) &&
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 379f4969d0bd..a655f172b5ad 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -1391,6 +1391,12 @@ static bool access_mte_regs(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
 	return false;
 }
 
+static unsigned int mte_visibility(const struct kvm_vcpu *vcpu,
+				   const struct sys_reg_desc *rd)
+{
+	return REG_HIDDEN_USER | REG_HIDDEN_GUEST;
+}
+
 /* sys_reg_desc initialiser for known cpufeature ID registers */
 #define ID_SANITISED(name) {			\
 	SYS_DESC(SYS_##name),			\
@@ -1557,8 +1563,8 @@ static const struct sys_reg_desc sys_reg_descs[] = {
 	{ SYS_DESC(SYS_ACTLR_EL1), access_actlr, reset_actlr, ACTLR_EL1 },
 	{ SYS_DESC(SYS_CPACR_EL1), NULL, reset_val, CPACR_EL1, 0 },
 
-	{ SYS_DESC(SYS_RGSR_EL1), access_mte_regs },
-	{ SYS_DESC(SYS_GCR_EL1), access_mte_regs },
+	{ SYS_DESC(SYS_RGSR_EL1), access_mte_regs, reset_unknown, RGSR_EL1, .visibility = mte_visibility },
+	{ SYS_DESC(SYS_GCR_EL1), access_mte_regs, reset_unknown, GCR_EL1, .visibility = mte_visibility },
 
 	{ SYS_DESC(SYS_ZCR_EL1), NULL, reset_val, ZCR_EL1, 0, .visibility = sve_visibility },
 	{ SYS_DESC(SYS_TTBR0_EL1), access_vm_reg, reset_unknown, TTBR0_EL1 },
@@ -1584,8 +1590,8 @@ static const struct sys_reg_desc sys_reg_descs[] = {
 	{ SYS_DESC(SYS_ERXMISC0_EL1), trap_raz_wi },
 	{ SYS_DESC(SYS_ERXMISC1_EL1), trap_raz_wi },
 
-	{ SYS_DESC(SYS_TFSR_EL1), access_mte_regs },
-	{ SYS_DESC(SYS_TFSRE0_EL1), access_mte_regs },
+	{ SYS_DESC(SYS_TFSR_EL1), access_mte_regs, reset_unknown, TFSR_EL1, .visibility = mte_visibility },
+	{ SYS_DESC(SYS_TFSRE0_EL1), access_mte_regs, reset_unknown, TFSRE0_EL1, .visibility = mte_visibility },
 
 	{ SYS_DESC(SYS_FAR_EL1), access_vm_reg, reset_unknown, FAR_EL1 },
 	{ SYS_DESC(SYS_PAR_EL1), NULL, reset_unknown, PAR_EL1 },
-- 
2.20.1

