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From: Marc Zyngier <maz@kernel.org>
To: linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu
Cc: kernel-team@android.com,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>, Ard Biesheuvel <ardb@kernel.org>
Subject: [PATCH v2 12/17] arm64: Allow ID_AA64MMFR1_EL1.VH to be overridden from the command line
Date: Mon,  4 Jan 2021 13:50:06 +0000	[thread overview]
Message-ID: <20210104135011.2063104-13-maz@kernel.org> (raw)
In-Reply-To: <20210104135011.2063104-1-maz@kernel.org>

As we want to be able to disable VHE at runtime, let's match
"id_aa64mmfr1.vh=" from the command line as an override.
This doesn't have much effect yet as out boot code doesn't look
at the cpufeature, but only at the HW registers.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/include/asm/cpufeature.h |  3 +++
 arch/arm64/kernel/cpufeature.c      |  6 +++++-
 arch/arm64/kernel/idreg-override.c  | 12 ++++++++++++
 3 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
index 465d2cb63bfc..ef9487dfadca 100644
--- a/arch/arm64/include/asm/cpufeature.h
+++ b/arch/arm64/include/asm/cpufeature.h
@@ -813,6 +813,9 @@ static inline unsigned int get_vmid_bits(u64 mmfr1)
 	return 8;
 }
 
+extern u64 id_aa64mmfr1_val;
+extern u64 id_aa64mmfr1_mask;
+
 u32 get_kvm_ipa_limit(void);
 void dump_cpu_features(void);
 
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 2dbfc0096b0d..623a74090c9e 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -555,6 +555,9 @@ static const struct arm64_ftr_bits ftr_raz[] = {
 
 #define ARM64_FTR_REG(id, table) ARM64_FTR_REG_OVERRIDE(id, table, NULL, NULL)
 
+u64 id_aa64mmfr1_val;
+u64 id_aa64mmfr1_mask;
+
 static const struct __ftr_reg_entry {
 	u32			sys_id;
 	struct arm64_ftr_reg 	*reg;
@@ -602,7 +605,8 @@ static const struct __ftr_reg_entry {
 
 	/* Op1 = 0, CRn = 0, CRm = 7 */
 	ARM64_FTR_REG(SYS_ID_AA64MMFR0_EL1, ftr_id_aa64mmfr0),
-	ARM64_FTR_REG(SYS_ID_AA64MMFR1_EL1, ftr_id_aa64mmfr1),
+	ARM64_FTR_REG_OVERRIDE(SYS_ID_AA64MMFR1_EL1, ftr_id_aa64mmfr1,
+			       &id_aa64mmfr1_val, &id_aa64mmfr1_mask),
 	ARM64_FTR_REG(SYS_ID_AA64MMFR2_EL1, ftr_id_aa64mmfr2),
 
 	/* Op1 = 0, CRn = 1, CRm = 2 */
diff --git a/arch/arm64/kernel/idreg-override.c b/arch/arm64/kernel/idreg-override.c
index 392f93b67103..75d9845f489b 100644
--- a/arch/arm64/kernel/idreg-override.c
+++ b/arch/arm64/kernel/idreg-override.c
@@ -10,6 +10,7 @@
 #include <linux/libfdt.h>
 
 #include <asm/cacheflush.h>
+#include <asm/cpufeature.h>
 #include <asm/setup.h>
 
 struct reg_desc {
@@ -22,7 +23,18 @@ struct reg_desc {
 	} 			fields[];
 };
 
+static const struct reg_desc mmfr1 __initdata = {
+	.name		= "id_aa64mmfr1",
+	.val		= &id_aa64mmfr1_val,
+	.mask		= &id_aa64mmfr1_mask,
+	.fields		= {
+	        { "vh", ID_AA64MMFR1_VHE_SHIFT },
+		{}
+	},
+};
+
 static const struct reg_desc * const regs[] __initdata = {
+	&mmfr1,
 };
 
 static int __init find_field(const char *cmdline, const struct reg_desc *reg,
-- 
2.29.2

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  parent reply	other threads:[~2021-01-04 14:20 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-04 13:49 [PATCH v2 00/17] arm64: Early CPU feature override, and an application to VHE Marc Zyngier
2021-01-04 13:49 ` [PATCH v2 01/17] arm64: Fix labels in el2_setup macros Marc Zyngier
2021-01-04 13:49 ` [PATCH v2 02/17] arm64: Fix outdated TCR setup comment Marc Zyngier
2021-01-04 13:49 ` [PATCH v2 03/17] arm64: Turn the MMU-on sequence into a macro Marc Zyngier
2021-01-04 13:49 ` [PATCH v2 04/17] arm64: Provide an 'upgrade to VHE' stub hypercall Marc Zyngier
2021-01-05 20:35   ` Jing Zhang
2021-01-05 21:03     ` Marc Zyngier
2021-01-04 13:49 ` [PATCH v2 05/17] arm64: Initialise as nVHE before switching to VHE Marc Zyngier
2021-01-04 13:50 ` [PATCH v2 06/17] arm64: Move VHE-specific SPE setup to mutate_to_vhe() Marc Zyngier
2021-01-04 13:50 ` [PATCH v2 07/17] arm64: Simplify init_el2_state to be non-VHE only Marc Zyngier
2021-01-04 13:50 ` [PATCH v2 08/17] arm64: Move SCTLR_EL1 initialisation to EL-agnostic code Marc Zyngier
2021-01-04 13:50 ` [PATCH v2 09/17] arm64: cpufeature: Add global feature override facility Marc Zyngier
2021-01-04 13:50 ` [PATCH v2 10/17] arm64: Extract early FDT mapping from kaslr_early_init() Marc Zyngier
2021-01-04 13:50 ` [PATCH v2 11/17] arm64: cpufeature: Add an early command-line cpufeature override facility Marc Zyngier
2021-01-06  2:16   ` Jing Zhang
2021-01-06  9:03     ` Marc Zyngier
2021-01-04 13:50 ` Marc Zyngier [this message]
2021-01-05 22:42   ` [PATCH v2 12/17] arm64: Allow ID_AA64MMFR1_EL1.VH to be overridden from the command line Jing Zhang
2021-01-04 13:50 ` [PATCH v2 13/17] arm64: Honor VHE being disabled from the command-line Marc Zyngier
2021-01-04 13:50 ` [PATCH v2 14/17] arm64: Add an aliasing facility for the idreg override Marc Zyngier
2021-01-04 13:50 ` [PATCH v2 15/17] arm64: Make kvm-arm.mode={nvhe, protected} an alias of id_aa64mmfr1.vh=0 Marc Zyngier
2021-01-04 13:50 ` [PATCH v2 16/17] KVM: arm64: Document HVC_VHE_RESTART stub hypercall Marc Zyngier
2021-01-05 22:58   ` Jing Zhang
2021-01-04 13:50 ` [PATCH v2 17/17] arm64: Move "nokaslr" over to the early cpufeature infrastructure Marc Zyngier

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