From 45879a57751d272ced9ed5ccfd28c58e2095ceb7 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Wed, 10 Mar 2021 13:25:57 +0000 Subject: [PATCH 1/4] arm64: Use INIT_SCTLR_EL1_MMU_OFF to disable the MMU on CPU restart Instead of doing a RMW on SCTLR_EL1 to disable the MMU, use the existing define that loads the right set of bits. Acked-by: Will Deacon Acked-by: Mark Rutland Signed-off-by: Marc Zyngier --- arch/arm64/kernel/cpu-reset.S | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) diff --git a/arch/arm64/kernel/cpu-reset.S b/arch/arm64/kernel/cpu-reset.S index 37721eb6f9a1..d47ff63a5b66 100644 --- a/arch/arm64/kernel/cpu-reset.S +++ b/arch/arm64/kernel/cpu-reset.S @@ -30,10 +30,7 @@ * flat identity mapping. */ SYM_CODE_START(__cpu_soft_restart) - /* Clear sctlr_el1 flags. */ - mrs x12, sctlr_el1 - mov_q x13, SCTLR_ELx_FLAGS - bic x12, x12, x13 + mov_q x12, INIT_SCTLR_EL1_MMU_OFF pre_disable_mmu_workaround /* * either disable EL1&0 translation regime or disable EL2&0 translation From bc6ddaa67abc9345370b219d07b079d25665f868 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Wed, 10 Mar 2021 13:32:53 +0000 Subject: [PATCH 2/4] KVM: arm64: Use INIT_SCTLR_EL2_MMU_OFF to disable the MMU on KVM teardown Instead of doing a RMW on SCTLR_EL2 to disable the MMU, use the existing define that loads the right set of bits. Acked-by: Will Deacon Acked-by: Mark Rutland Signed-off-by: Marc Zyngier --- arch/arm64/kvm/hyp/nvhe/hyp-init.S | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-init.S b/arch/arm64/kvm/hyp/nvhe/hyp-init.S index c631e29fb001..4eb584ae13d9 100644 --- a/arch/arm64/kvm/hyp/nvhe/hyp-init.S +++ b/arch/arm64/kvm/hyp/nvhe/hyp-init.S @@ -221,9 +221,7 @@ SYM_CODE_START(__kvm_handle_stub_hvc) mov x0, xzr reset: /* Reset kvm back to the hyp stub. */ - mrs x5, sctlr_el2 - mov_q x6, SCTLR_ELx_FLAGS - bic x5, x5, x6 // Clear SCTL_M and etc + mov_q x5, INIT_SCTLR_EL2_MMU_OFF pre_disable_mmu_workaround msr sctlr_el2, x5 isb From fe2c8d19189e23a951e45fdb73aade25b1665bce Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Wed, 10 Mar 2021 13:33:20 +0000 Subject: [PATCH 3/4] KVM: arm64: Turn SCTLR_ELx_FLAGS into INIT_SCTLR_EL2_MMU_ON Only the nVHE EL2 code is using this define, so let's make it plain that it is EL2 only, and refactor it to contain all the bits we need when configuring the EL2 MMU, and only those. Acked-by: Will Deacon Acked-by: Mark Rutland Signed-off-by: Marc Zyngier --- arch/arm64/include/asm/sysreg.h | 7 ++++--- arch/arm64/kvm/hyp/nvhe/hyp-init.S | 8 +------- 2 files changed, 5 insertions(+), 10 deletions(-) diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h index d4a5fca984c3..ab24d9e7eef1 100644 --- a/arch/arm64/include/asm/sysreg.h +++ b/arch/arm64/include/asm/sysreg.h @@ -579,9 +579,6 @@ #define SCTLR_ELx_A (BIT(1)) #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_EL2 specific flags. */ #define SCTLR_EL2_RES1 ((BIT(4)) | (BIT(5)) | (BIT(11)) | (BIT(16)) | \ (BIT(18)) | (BIT(22)) | (BIT(23)) | (BIT(28)) | \ @@ -593,6 +590,10 @@ #define ENDIAN_SET_EL2 0 #endif +#define INIT_SCTLR_EL2_MMU_ON \ + (SCTLR_ELx_M | SCTLR_ELx_C | SCTLR_ELx_SA | SCTLR_ELx_I | \ + SCTLR_ELx_IESB | ENDIAN_SET_EL2 | SCTLR_EL2_RES1) + #define INIT_SCTLR_EL2_MMU_OFF \ (SCTLR_EL2_RES1 | ENDIAN_SET_EL2) diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-init.S b/arch/arm64/kvm/hyp/nvhe/hyp-init.S index 4eb584ae13d9..2e16b2098bbd 100644 --- a/arch/arm64/kvm/hyp/nvhe/hyp-init.S +++ b/arch/arm64/kvm/hyp/nvhe/hyp-init.S @@ -117,13 +117,7 @@ alternative_else_nop_endif tlbi alle2 dsb sy - /* - * Preserve all the RES1 bits while setting the default flags, - * as well as the EE bit on BE. Drop the A flag since the compiler - * is allowed to generate unaligned accesses. - */ - mov_q x0, (SCTLR_EL2_RES1 | (SCTLR_ELx_FLAGS & ~SCTLR_ELx_A)) -CPU_BE( orr x0, x0, #SCTLR_ELx_EE) + mov_q x0, INIT_SCTLR_EL2_MMU_ON alternative_if ARM64_HAS_ADDRESS_AUTH mov_q x1, (SCTLR_ELx_ENIA | SCTLR_ELx_ENIB | \ SCTLR_ELx_ENDA | SCTLR_ELx_ENDB) From c8a4b35f5063c256451a3508e9f0b9e6b49debbb Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Wed, 10 Mar 2021 13:34:26 +0000 Subject: [PATCH 4/4] KVM: arm64: Force SCTLR_EL2.WXN when running nVHE As the EL2 nVHE object is nicely split into sections and that we already use differenciating permissions for data and code, we can enable SCTLR_EL2.WXN so that we don't have to worry about misconfiguration of the page tables. Flip the WXN bit and get the ball running! Acked-by: Will Deacon Acked-by: Mark Rutland Signed-off-by: Marc Zyngier --- arch/arm64/include/asm/sysreg.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h index ab24d9e7eef1..70cbb0244e07 100644 --- a/arch/arm64/include/asm/sysreg.h +++ b/arch/arm64/include/asm/sysreg.h @@ -592,7 +592,7 @@ #define INIT_SCTLR_EL2_MMU_ON \ (SCTLR_ELx_M | SCTLR_ELx_C | SCTLR_ELx_SA | SCTLR_ELx_I | \ - SCTLR_ELx_IESB | ENDIAN_SET_EL2 | SCTLR_EL2_RES1) + SCTLR_ELx_IESB | SCTLR_ELx_WXN | ENDIAN_SET_EL2 | SCTLR_EL2_RES1) #define INIT_SCTLR_EL2_MMU_OFF \ (SCTLR_EL2_RES1 | ENDIAN_SET_EL2)