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linux/arch/arm64/kvm/hyp.S

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arm64: KVM: HYP mode world switch implementation The HYP mode world switch in all its glory. Implements save/restore of host/guest registers, EL2 trapping, IPA resolution, and additional services (tlb invalidation). Reviewed-by: Christopher Covington <cov@codeaurora.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2012-12-10 16:40:18 +00:00
/*
* Copyright (C) 2012,2013 - ARM Ltd
* Author: Marc Zyngier <marc.zyngier@arm.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/linkage.h>
arm64: KVM: VHE: Patch out use of HVC With VHE, the host never issues an HVC instruction to get into the KVM code, as we can simply branch there. Use runtime code patching to simplify things a bit. Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-01-29 13:52:12 +00:00
#include <asm/alternative.h>
arm64: kvm: move to ESR_ELx macros Now that we have common ESR_ELx macros, make use of them in the arm64 KVM code. The addition of <asm/esr.h> to the include path highlighted badly ordered (i.e. not alphabetical) include lists; these are changed to alphabetical order. There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Peter Maydell <peter.maydell@linaro.org> Cc: Will Deacon <will.deacon@arm.com>
2014-11-24 13:59:30 +00:00
#include <asm/assembler.h>
arm64: KVM: VHE: Patch out use of HVC With VHE, the host never issues an HVC instruction to get into the KVM code, as we can simply branch there. Use runtime code patching to simplify things a bit. Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-01-29 13:52:12 +00:00
#include <asm/cpufeature.h>
arm64: KVM: HYP mode world switch implementation The HYP mode world switch in all its glory. Implements save/restore of host/guest registers, EL2 trapping, IPA resolution, and additional services (tlb invalidation). Reviewed-by: Christopher Covington <cov@codeaurora.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2012-12-10 16:40:18 +00:00
arm/arm64: KVM: detect CPU reset on CPU_PM_EXIT Commit 1fcf7ce0c602 (arm: kvm: implement CPU PM notifier) added support for CPU power-management, using a cpu_notifier to re-init KVM on a CPU that entered CPU idle. The code assumed that a CPU entering idle would actually be powered off, loosing its state entierely, and would then need to be reinitialized. It turns out that this is not always the case, and some HW performs CPU PM without actually killing the core. In this case, we try to reinitialize KVM while it is still live. It ends up badly, as reported by Andre Przywara (using a Calxeda Midway): [ 3.663897] Kernel panic - not syncing: unexpected prefetch abort in Hyp mode at: 0x685760 [ 3.663897] unexpected data abort in Hyp mode at: 0xc067d150 [ 3.663897] unexpected HVC/SVC trap in Hyp mode at: 0xc0901dd0 The trick here is to detect if we've been through a full re-init or not by looking at HVBAR (VBAR_EL2 on arm64). This involves implementing the backend for __hyp_get_vectors in the main KVM HYP code (rather small), and checking the return value against the default one when the CPU notifier is called on CPU_PM_EXIT. Reported-by: Andre Przywara <osp@andrep.de> Tested-by: Andre Przywara <osp@andrep.de> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Cc: Rob Herring <rob.herring@linaro.org> Acked-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-02-26 18:47:36 +00:00
/*
arm64: kvm: deal with kernel symbols outside of linear mapping KVM on arm64 uses a fixed offset between the linear mapping at EL1 and the HYP mapping at EL2. Before we can move the kernel virtual mapping out of the linear mapping, we have to make sure that references to kernel symbols that are accessed via the HYP mapping are translated to their linear equivalent. Reviewed-by: Mark Rutland <mark.rutland@arm.com> Acked-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2016-02-16 13:52:39 +01:00
* u64 __kvm_call_hyp(void *hypfn, ...);
arm/arm64: KVM: detect CPU reset on CPU_PM_EXIT Commit 1fcf7ce0c602 (arm: kvm: implement CPU PM notifier) added support for CPU power-management, using a cpu_notifier to re-init KVM on a CPU that entered CPU idle. The code assumed that a CPU entering idle would actually be powered off, loosing its state entierely, and would then need to be reinitialized. It turns out that this is not always the case, and some HW performs CPU PM without actually killing the core. In this case, we try to reinitialize KVM while it is still live. It ends up badly, as reported by Andre Przywara (using a Calxeda Midway): [ 3.663897] Kernel panic - not syncing: unexpected prefetch abort in Hyp mode at: 0x685760 [ 3.663897] unexpected data abort in Hyp mode at: 0xc067d150 [ 3.663897] unexpected HVC/SVC trap in Hyp mode at: 0xc0901dd0 The trick here is to detect if we've been through a full re-init or not by looking at HVBAR (VBAR_EL2 on arm64). This involves implementing the backend for __hyp_get_vectors in the main KVM HYP code (rather small), and checking the return value against the default one when the CPU notifier is called on CPU_PM_EXIT. Reported-by: Andre Przywara <osp@andrep.de> Tested-by: Andre Przywara <osp@andrep.de> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Cc: Rob Herring <rob.herring@linaro.org> Acked-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-02-26 18:47:36 +00:00
*
* This is not really a variadic function in the classic C-way and care must
* be taken when calling this to ensure parameters are passed in registers
* only, since the stack will change between the caller and the callee.
*
* Call the function with the first argument containing a pointer to the
* function you wish to call in Hyp mode, and subsequent arguments will be
* passed as x0, x1, and x2 (a maximum of 3 arguments in addition to the
* function pointer can be passed). The function being called must be mapped
* in Hyp mode (see init_hyp_mode in arch/arm/kvm/arm.c). Return values are
arm64: KVM: Move away from the assembly version of the world switch This is it. We remove all of the code that has now been rewritten. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Acked-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-10-25 15:51:41 +00:00
* passed in x0.
arm/arm64: KVM: detect CPU reset on CPU_PM_EXIT Commit 1fcf7ce0c602 (arm: kvm: implement CPU PM notifier) added support for CPU power-management, using a cpu_notifier to re-init KVM on a CPU that entered CPU idle. The code assumed that a CPU entering idle would actually be powered off, loosing its state entierely, and would then need to be reinitialized. It turns out that this is not always the case, and some HW performs CPU PM without actually killing the core. In this case, we try to reinitialize KVM while it is still live. It ends up badly, as reported by Andre Przywara (using a Calxeda Midway): [ 3.663897] Kernel panic - not syncing: unexpected prefetch abort in Hyp mode at: 0x685760 [ 3.663897] unexpected data abort in Hyp mode at: 0xc067d150 [ 3.663897] unexpected HVC/SVC trap in Hyp mode at: 0xc0901dd0 The trick here is to detect if we've been through a full re-init or not by looking at HVBAR (VBAR_EL2 on arm64). This involves implementing the backend for __hyp_get_vectors in the main KVM HYP code (rather small), and checking the return value against the default one when the CPU notifier is called on CPU_PM_EXIT. Reported-by: Andre Przywara <osp@andrep.de> Tested-by: Andre Przywara <osp@andrep.de> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Cc: Rob Herring <rob.herring@linaro.org> Acked-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-02-26 18:47:36 +00:00
*
* A function pointer with a value of 0 has a special meaning, and is
* used to implement __hyp_get_vectors in the same way as in
* arch/arm64/kernel/hyp_stub.S.
*/
arm64: kvm: deal with kernel symbols outside of linear mapping KVM on arm64 uses a fixed offset between the linear mapping at EL1 and the HYP mapping at EL2. Before we can move the kernel virtual mapping out of the linear mapping, we have to make sure that references to kernel symbols that are accessed via the HYP mapping are translated to their linear equivalent. Reviewed-by: Mark Rutland <mark.rutland@arm.com> Acked-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2016-02-16 13:52:39 +01:00
ENTRY(__kvm_call_hyp)
arm64: KVM: VHE: Patch out use of HVC With VHE, the host never issues an HVC instruction to get into the KVM code, as we can simply branch there. Use runtime code patching to simplify things a bit. Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-01-29 13:52:12 +00:00
alternative_if_not ARM64_HAS_VIRT_HOST_EXTN
arm64: KVM: HYP mode world switch implementation The HYP mode world switch in all its glory. Implements save/restore of host/guest registers, EL2 trapping, IPA resolution, and additional services (tlb invalidation). Reviewed-by: Christopher Covington <cov@codeaurora.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2012-12-10 16:40:18 +00:00
hvc #0
ret
arm64: KVM: VHE: Patch out use of HVC With VHE, the host never issues an HVC instruction to get into the KVM code, as we can simply branch there. Use runtime code patching to simplify things a bit. Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-01-29 13:52:12 +00:00
alternative_else
b __vhe_hyp_call
nop
alternative_endif
arm64: kvm: deal with kernel symbols outside of linear mapping KVM on arm64 uses a fixed offset between the linear mapping at EL1 and the HYP mapping at EL2. Before we can move the kernel virtual mapping out of the linear mapping, we have to make sure that references to kernel symbols that are accessed via the HYP mapping are translated to their linear equivalent. Reviewed-by: Mark Rutland <mark.rutland@arm.com> Acked-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2016-02-16 13:52:39 +01:00
ENDPROC(__kvm_call_hyp)
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