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c94b0cf282
A later patch implements kvm_arch_hardware_disable(), to remove kvm from el2, and re-instate the hyp-stub. This can happen while guests are running, particularly when kvm_reboot() calls kvm_arch_hardware_disable() on each cpu. This can interrupt a guest, remove kvm, then allow the guest to be scheduled again. This causes kvm_call_hyp() to be run against the hyp-stub. Change the hyp-stub to return a new exception type when this happens, and add code to kvm's handle_exit() to tell userspace we failed to enter the guest. Signed-off-by: James Morse <james.morse@arm.com> Acked-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
132 lines
3.4 KiB
ArmAsm
132 lines
3.4 KiB
ArmAsm
/*
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* Hypervisor stub
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*
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* Copyright (C) 2012 ARM Ltd.
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* Author: Marc Zyngier <marc.zyngier@arm.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <linux/init.h>
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#include <linux/linkage.h>
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#include <linux/irqchip/arm-gic-v3.h>
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#include <asm/assembler.h>
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#include <asm/kvm_arm.h>
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#include <asm/kvm_asm.h>
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#include <asm/ptrace.h>
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#include <asm/virt.h>
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.text
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.align 11
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ENTRY(__hyp_stub_vectors)
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ventry el2_sync_invalid // Synchronous EL2t
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ventry el2_irq_invalid // IRQ EL2t
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ventry el2_fiq_invalid // FIQ EL2t
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ventry el2_error_invalid // Error EL2t
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ventry el2_sync_invalid // Synchronous EL2h
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ventry el2_irq_invalid // IRQ EL2h
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ventry el2_fiq_invalid // FIQ EL2h
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ventry el2_error_invalid // Error EL2h
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ventry el1_sync // Synchronous 64-bit EL1
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ventry el1_irq_invalid // IRQ 64-bit EL1
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ventry el1_fiq_invalid // FIQ 64-bit EL1
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ventry el1_error_invalid // Error 64-bit EL1
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ventry el1_sync_invalid // Synchronous 32-bit EL1
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ventry el1_irq_invalid // IRQ 32-bit EL1
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ventry el1_fiq_invalid // FIQ 32-bit EL1
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ventry el1_error_invalid // Error 32-bit EL1
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ENDPROC(__hyp_stub_vectors)
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.align 11
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el1_sync:
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mrs x30, esr_el2
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lsr x30, x30, #ESR_ELx_EC_SHIFT
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cmp x30, #ESR_ELx_EC_HVC64
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b.ne 9f // Not an HVC trap
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cmp x0, #HVC_GET_VECTORS
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b.ne 1f
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mrs x0, vbar_el2
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b 9f
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1: cmp x0, #HVC_SET_VECTORS
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b.ne 2f
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msr vbar_el2, x1
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b 9f
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/* Someone called kvm_call_hyp() against the hyp-stub... */
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2: mov x0, #ARM_EXCEPTION_HYP_GONE
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9: eret
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ENDPROC(el1_sync)
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.macro invalid_vector label
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\label:
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b \label
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ENDPROC(\label)
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.endm
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invalid_vector el2_sync_invalid
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invalid_vector el2_irq_invalid
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invalid_vector el2_fiq_invalid
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invalid_vector el2_error_invalid
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invalid_vector el1_sync_invalid
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invalid_vector el1_irq_invalid
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invalid_vector el1_fiq_invalid
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invalid_vector el1_error_invalid
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/*
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* __hyp_set_vectors: Call this after boot to set the initial hypervisor
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* vectors as part of hypervisor installation. On an SMP system, this should
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* be called on each CPU.
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*
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* x0 must be the physical address of the new vector table, and must be
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* 2KB aligned.
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*
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* Before calling this, you must check that the stub hypervisor is installed
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* everywhere, by waiting for any secondary CPUs to be brought up and then
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* checking that is_hyp_mode_available() is true.
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*
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* If not, there is a pre-existing hypervisor, some CPUs failed to boot, or
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* something else went wrong... in such cases, trying to install a new
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* hypervisor is unlikely to work as desired.
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*
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* When you call into your shiny new hypervisor, sp_el2 will contain junk,
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* so you will need to set that to something sensible at the new hypervisor's
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* initialisation entry point.
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*/
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ENTRY(__hyp_get_vectors)
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str lr, [sp, #-16]!
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mov x0, #HVC_GET_VECTORS
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hvc #0
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ldr lr, [sp], #16
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ret
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ENDPROC(__hyp_get_vectors)
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ENTRY(__hyp_set_vectors)
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str lr, [sp, #-16]!
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mov x1, x0
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mov x0, #HVC_SET_VECTORS
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hvc #0
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ldr lr, [sp], #16
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ret
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ENDPROC(__hyp_set_vectors)
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