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 04/17] arm64: Provide an 'upgrade to VHE' stub hypercall Date: Mon, 28 Dec 2020 10:49:45 +0000 [thread overview] Message-ID: <20201228104958.1848833-5-maz@kernel.org> (raw) In-Reply-To: <20201228104958.1848833-1-maz@kernel.org> As we are about to change the way a VHE system boots, let's provide the core helper, in the form of a stub hypercall that enables VHE and replicates the full EL1 context at EL2, thanks to EL1 and VHE-EL2 being extremely similar. On exception return, the kernel carries on at EL2. Fancy! Nothing calls this new hypercall yet, so no functional change. Signed-off-by: Marc Zyngier <maz@kernel.org> --- arch/arm64/include/asm/virt.h | 7 +++- arch/arm64/kernel/hyp-stub.S | 70 ++++++++++++++++++++++++++++++++++- 2 files changed, 74 insertions(+), 3 deletions(-) diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h index ee6a48df89d9..7379f35ae2c6 100644 --- a/arch/arm64/include/asm/virt.h +++ b/arch/arm64/include/asm/virt.h @@ -35,8 +35,13 @@ */ #define HVC_RESET_VECTORS 2 +/* + * HVC_VHE_RESTART - Upgrade the CPU from EL1 to EL2, if possible + */ +#define HVC_VHE_RESTART 3 + /* Max number of HYP stub hypercalls */ -#define HVC_STUB_HCALL_NR 3 +#define HVC_STUB_HCALL_NR 4 /* Error returned when an invalid stub number is passed into x0 */ #define HVC_STUB_ERR 0xbadca11 diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S index 160f5881a0b7..6ffdc1f7778b 100644 --- a/arch/arm64/kernel/hyp-stub.S +++ b/arch/arm64/kernel/hyp-stub.S @@ -8,9 +8,9 @@ #include <linux/init.h> #include <linux/linkage.h> -#include <linux/irqchip/arm-gic-v3.h> #include <asm/assembler.h> +#include <asm/el2_setup.h> #include <asm/kvm_arm.h> #include <asm/kvm_asm.h> #include <asm/ptrace.h> @@ -47,10 +47,16 @@ SYM_CODE_END(__hyp_stub_vectors) SYM_CODE_START_LOCAL(el1_sync) cmp x0, #HVC_SET_VECTORS - b.ne 2f + b.ne 1f msr vbar_el2, x1 b 9f +1: cmp x0, #HVC_VHE_RESTART + b.ne 2f + mov x0, #HVC_SOFT_RESTART + adr x1, mutate_to_vhe + // fall through... + 2: cmp x0, #HVC_SOFT_RESTART b.ne 3f mov x0, x2 @@ -70,6 +76,66 @@ SYM_CODE_START_LOCAL(el1_sync) eret SYM_CODE_END(el1_sync) +// nVHE? No way! Give me the real thing! +SYM_CODE_START_LOCAL(mutate_to_vhe) + // Sanity check: MMU *must* be off + mrs x0, sctlr_el2 + tbnz x0, #0, 1f + + // Needs to be VHE capable, obviously + mrs x0, id_aa64mmfr1_el1 + ubfx x0, x0, #ID_AA64MMFR1_VHE_SHIFT, #4 + cbz x0, 1f + + // Engage the VHE magic! + mov_q x0, HCR_HOST_VHE_FLAGS + msr hcr_el2, x0 + isb + + // Doesn't do much on VHE, but still, worth a shot + init_el2_state vhe + + // Use the EL1 allocated stack, per-cpu offset + mrs x0, sp_el1 + mov sp, x0 + mrs x0, tpidr_el1 + msr tpidr_el2, x0 + + // FP configuration, vectors + mrs_s x0, SYS_CPACR_EL12 + msr cpacr_el1, x0 + mrs_s x0, SYS_VBAR_EL12 + msr vbar_el1, x0 + + // Transfert the MM state from EL1 to EL2 + mrs_s x0, SYS_TCR_EL12 + msr tcr_el1, x0 + mrs_s x0, SYS_TTBR0_EL12 + msr ttbr0_el1, x0 + mrs_s x0, SYS_TTBR1_EL12 + msr ttbr1_el1, x0 + mrs_s x0, SYS_MAIR_EL12 + msr mair_el1, x0 + isb + + // Invalidate TLBs before enabling the MMU + tlbi vmalle1 + dsb nsh + + // Enable the EL2 S1 MMU, as set up from EL1 + mrs_s x0, SYS_SCTLR_EL12 + set_sctlr_el1 x0 + + // Hack the exception return to stay at EL2 + mrs x0, spsr_el1 + and x0, x0, #~PSR_MODE_MASK + mov x1, #PSR_MODE_EL2h + orr x0, x0, x1 + msr spsr_el1, x0 + +1: eret +SYM_CODE_END(mutate_to_vhe) + .macro invalid_vector label SYM_CODE_START_LOCAL(\label) b \label -- 2.29.2 _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
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From: Marc Zyngier <maz@kernel.org> To: linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu Cc: Mark Rutland <mark.rutland@arm.com>, kernel-team@android.com, Suzuki K Poulose <suzuki.poulose@arm.com>, Catalin Marinas <catalin.marinas@arm.com>, Alexandru Elisei <alexandru.elisei@arm.com>, James Morse <james.morse@arm.com>, David Brazdil <dbrazdil@google.com>, Will Deacon <will@kernel.org>, Ard Biesheuvel <ardb@kernel.org>, Julien Thierry <julien.thierry.kdev@gmail.com> Subject: [PATCH 04/17] arm64: Provide an 'upgrade to VHE' stub hypercall Date: Mon, 28 Dec 2020 10:49:45 +0000 [thread overview] Message-ID: <20201228104958.1848833-5-maz@kernel.org> (raw) In-Reply-To: <20201228104958.1848833-1-maz@kernel.org> As we are about to change the way a VHE system boots, let's provide the core helper, in the form of a stub hypercall that enables VHE and replicates the full EL1 context at EL2, thanks to EL1 and VHE-EL2 being extremely similar. On exception return, the kernel carries on at EL2. Fancy! Nothing calls this new hypercall yet, so no functional change. Signed-off-by: Marc Zyngier <maz@kernel.org> --- arch/arm64/include/asm/virt.h | 7 +++- arch/arm64/kernel/hyp-stub.S | 70 ++++++++++++++++++++++++++++++++++- 2 files changed, 74 insertions(+), 3 deletions(-) diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h index ee6a48df89d9..7379f35ae2c6 100644 --- a/arch/arm64/include/asm/virt.h +++ b/arch/arm64/include/asm/virt.h @@ -35,8 +35,13 @@ */ #define HVC_RESET_VECTORS 2 +/* + * HVC_VHE_RESTART - Upgrade the CPU from EL1 to EL2, if possible + */ +#define HVC_VHE_RESTART 3 + /* Max number of HYP stub hypercalls */ -#define HVC_STUB_HCALL_NR 3 +#define HVC_STUB_HCALL_NR 4 /* Error returned when an invalid stub number is passed into x0 */ #define HVC_STUB_ERR 0xbadca11 diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S index 160f5881a0b7..6ffdc1f7778b 100644 --- a/arch/arm64/kernel/hyp-stub.S +++ b/arch/arm64/kernel/hyp-stub.S @@ -8,9 +8,9 @@ #include <linux/init.h> #include <linux/linkage.h> -#include <linux/irqchip/arm-gic-v3.h> #include <asm/assembler.h> +#include <asm/el2_setup.h> #include <asm/kvm_arm.h> #include <asm/kvm_asm.h> #include <asm/ptrace.h> @@ -47,10 +47,16 @@ SYM_CODE_END(__hyp_stub_vectors) SYM_CODE_START_LOCAL(el1_sync) cmp x0, #HVC_SET_VECTORS - b.ne 2f + b.ne 1f msr vbar_el2, x1 b 9f +1: cmp x0, #HVC_VHE_RESTART + b.ne 2f + mov x0, #HVC_SOFT_RESTART + adr x1, mutate_to_vhe + // fall through... + 2: cmp x0, #HVC_SOFT_RESTART b.ne 3f mov x0, x2 @@ -70,6 +76,66 @@ SYM_CODE_START_LOCAL(el1_sync) eret SYM_CODE_END(el1_sync) +// nVHE? No way! Give me the real thing! +SYM_CODE_START_LOCAL(mutate_to_vhe) + // Sanity check: MMU *must* be off + mrs x0, sctlr_el2 + tbnz x0, #0, 1f + + // Needs to be VHE capable, obviously + mrs x0, id_aa64mmfr1_el1 + ubfx x0, x0, #ID_AA64MMFR1_VHE_SHIFT, #4 + cbz x0, 1f + + // Engage the VHE magic! + mov_q x0, HCR_HOST_VHE_FLAGS + msr hcr_el2, x0 + isb + + // Doesn't do much on VHE, but still, worth a shot + init_el2_state vhe + + // Use the EL1 allocated stack, per-cpu offset + mrs x0, sp_el1 + mov sp, x0 + mrs x0, tpidr_el1 + msr tpidr_el2, x0 + + // FP configuration, vectors + mrs_s x0, SYS_CPACR_EL12 + msr cpacr_el1, x0 + mrs_s x0, SYS_VBAR_EL12 + msr vbar_el1, x0 + + // Transfert the MM state from EL1 to EL2 + mrs_s x0, SYS_TCR_EL12 + msr tcr_el1, x0 + mrs_s x0, SYS_TTBR0_EL12 + msr ttbr0_el1, x0 + mrs_s x0, SYS_TTBR1_EL12 + msr ttbr1_el1, x0 + mrs_s x0, SYS_MAIR_EL12 + msr mair_el1, x0 + isb + + // Invalidate TLBs before enabling the MMU + tlbi vmalle1 + dsb nsh + + // Enable the EL2 S1 MMU, as set up from EL1 + mrs_s x0, SYS_SCTLR_EL12 + set_sctlr_el1 x0 + + // Hack the exception return to stay at EL2 + mrs x0, spsr_el1 + and x0, x0, #~PSR_MODE_MASK + mov x1, #PSR_MODE_EL2h + orr x0, x0, x1 + msr spsr_el1, x0 + +1: eret +SYM_CODE_END(mutate_to_vhe) + .macro invalid_vector label SYM_CODE_START_LOCAL(\label) b \label -- 2.29.2 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2020-12-28 10:50 UTC|newest] Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-12-28 10:49 [PATCH 00/17] arm64: Early CPU feature override, and an application to VHE Marc Zyngier 2020-12-28 10:49 ` Marc Zyngier 2020-12-28 10:49 ` [PATCH 01/17] arm64: Fix labels in el2_setup macros Marc Zyngier 2020-12-28 10:49 ` Marc Zyngier 2020-12-28 10:49 ` [PATCH 02/17] arm64: Fix outdated TCR setup comment Marc Zyngier 2020-12-28 10:49 ` Marc Zyngier 2020-12-28 10:49 ` [PATCH 03/17] arm64: Turn the MMU-on sequence into a macro Marc Zyngier 2020-12-28 10:49 ` Marc Zyngier 2020-12-28 10:49 ` Marc Zyngier [this message] 2020-12-28 10:49 ` [PATCH 04/17] arm64: Provide an 'upgrade to VHE' stub hypercall Marc Zyngier 2021-01-04 23:39 ` Jing Zhang 2021-01-04 23:39 ` Jing Zhang 2021-01-05 8:24 ` Marc Zyngier 2021-01-05 8:24 ` Marc Zyngier 2020-12-28 10:49 ` [PATCH 05/17] arm64: Initialise as nVHE before switching to VHE Marc Zyngier 2020-12-28 10:49 ` Marc Zyngier 2020-12-28 10:49 ` [PATCH 06/17] arm64: Move VHE-specific SPE setup to mutate_to_vhe() Marc Zyngier 2020-12-28 10:49 ` Marc Zyngier 2020-12-28 10:49 ` [PATCH 07/17] arm64: Simplify init_el2_state to be non-VHE only Marc Zyngier 2020-12-28 10:49 ` Marc Zyngier 2020-12-28 10:49 ` [PATCH 08/17] arm64: Move SCTLR_EL1 initialisation to EL-agnostic code Marc Zyngier 2020-12-28 10:49 ` Marc Zyngier 2020-12-28 10:49 ` [PATCH 09/17] arm64: cpufeature: Add global feature override facility Marc Zyngier 2020-12-28 10:49 ` Marc Zyngier 2020-12-28 10:49 ` [PATCH 10/17] arm64: Extract early FDT mapping from kaslr_early_init() Marc Zyngier 2020-12-28 10:49 ` Marc Zyngier 2020-12-28 10:49 ` [PATCH 11/17] arm64: cpufeature: Add an early command-line cpufeature override facility Marc Zyngier 2020-12-28 10:49 ` Marc Zyngier 2020-12-28 10:49 ` [PATCH 12/17] arm64: Allow ID_AA64MMFR1_EL1.VH to be overridden from the command line Marc Zyngier 2020-12-28 10:49 ` Marc Zyngier 2020-12-28 10:49 ` [PATCH 13/17] arm64: Honor VHE being disabled from the command-line Marc Zyngier 2020-12-28 10:49 ` Marc Zyngier 2020-12-28 10:49 ` [PATCH 14/17] arm64: Add an aliasing facility for the idreg override Marc Zyngier 2020-12-28 10:49 ` Marc Zyngier 2020-12-28 10:49 ` [PATCH 15/17] arm64: Make kvm-arm.mode={nvhe, protected} an alias of id_aa64mmfr1.vh=0 Marc Zyngier 2020-12-28 10:49 ` Marc Zyngier 2020-12-28 10:49 ` [PATCH 16/17] KVM: arm64: Document HVC_VHE_RESTART stub hypercall Marc Zyngier 2020-12-28 10:49 ` Marc Zyngier 2020-12-28 10:49 ` [PATCH 17/17] arm64: Move "nokaslr" over to the early cpufeature infrastructure Marc Zyngier 2020-12-28 10:49 ` Marc Zyngier 2020-12-29 19:27 ` [PATCH 00/17] arm64: Early CPU feature override, and an application to VHE Marc Zyngier 2020-12-29 19:27 ` Marc Zyngier
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