From: marc.zyngier@arm.com (Marc Zyngier)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v8 05/13] arm64: kvm: allows kvm cpu hotplug
Date: Tue, 26 Apr 2016 17:26:04 +0100 [thread overview]
Message-ID: <571F969C.80200@arm.com> (raw)
In-Reply-To: <1461604250-12789-6-git-send-email-james.morse@arm.com>
Hi James,
On 25/04/16 18:10, James Morse wrote:
> From: AKASHI Takahiro <takahiro.akashi@linaro.org>
>
> The current kvm implementation on arm64 does cpu-specific initialization
> at system boot, and has no way to gracefully shutdown a core in terms of
> kvm. This prevents kexec from rebooting the system at EL2.
>
> This patch adds a cpu tear-down function and also puts an existing cpu-init
> code into a separate function, kvm_arch_hardware_disable() and
> kvm_arch_hardware_enable() respectively.
> We don't need the arm64 specific cpu hotplug hook any more.
>
> Since this patch modifies common code between arm and arm64, one stub
> definition, __cpu_reset_hyp_mode(), is added on arm side to avoid
> compilation errors.
>
> Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
> [Rebase, added separate VHE init/exit path, changed resets use of
> kvm_call_hyp() to the __version, en/disabled hardware in init_subsystems(),
> added icache maintenance to __kvm_hyp_reset() and removed lr restore, removed
> guest-enter after teardown handling]
> Signed-off-by: James Morse <james.morse@arm.com>
>
> CC: Marc Zyngier <marc.zyngier@arm.com>
> ---
> N.B. this patch conflicts with 06a71a24bae5 ("arm64: KVM: unregister notifiers
> in hyp mode teardown path") in v4.6-rc4. See the cover letter for details.
>
> Changes since v7:
> * Moved the kvm-torn-down guest entry handling into handle_exit(),
> * Added an exception type for hyp-stub to return to any kvm_call_hyp() caller
>
> arch/arm/include/asm/kvm_host.h | 10 +++-
> arch/arm/include/asm/kvm_mmu.h | 1 +
> arch/arm/kvm/arm.c | 119 +++++++++++++++++++++++---------------
> arch/arm/kvm/mmu.c | 5 ++
> arch/arm64/include/asm/kvm_asm.h | 3 +
> arch/arm64/include/asm/kvm_host.h | 13 ++++-
> arch/arm64/include/asm/kvm_mmu.h | 1 +
> arch/arm64/kernel/hyp-stub.S | 5 +-
> arch/arm64/kvm/handle_exit.c | 7 +++
> arch/arm64/kvm/hyp-init.S | 38 ++++++++++++
> arch/arm64/kvm/reset.c | 14 +++++
> 11 files changed, 164 insertions(+), 52 deletions(-)
If you moved these hunks:
> diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
> index eb7490d232a0..a88da136f332 100644
> --- a/arch/arm64/include/asm/kvm_asm.h
> +++ b/arch/arm64/include/asm/kvm_asm.h
> @@ -22,6 +22,8 @@
>
> #define ARM_EXCEPTION_IRQ 0
> #define ARM_EXCEPTION_TRAP 1
> +/* The hyp-stub will return this for any kvm_call_hyp() call */
> +#define ARM_EXCEPTION_HYP_GONE 2
>
> #define KVM_ARM64_DEBUG_DIRTY_SHIFT 0
> #define KVM_ARM64_DEBUG_DIRTY (1 << KVM_ARM64_DEBUG_DIRTY_SHIFT)
> diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S
> index 894fb40fb378..8727f4490772 100644
> --- a/arch/arm64/kernel/hyp-stub.S
> +++ b/arch/arm64/kernel/hyp-stub.S
> @@ -23,6 +23,7 @@
>
> #include <asm/assembler.h>
> #include <asm/kvm_arm.h>
> +#include <asm/kvm_asm.h>
> #include <asm/ptrace.h>
> #include <asm/virt.h>
>
> @@ -70,8 +71,8 @@ el1_sync:
> msr vbar_el2, x1
> b 9f
>
> - /* Unrecognised call type */
> -2: mov x0, xzr
> + /* Someone called kvm_call_hyp() against the hyp-stub... */
> +2: mov x0, #ARM_EXCEPTION_HYP_GONE
>
> 9: eret
> ENDPROC(el1_sync)
> diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c
> index eba89e42f0ed..3246c4aba5b1 100644
> --- a/arch/arm64/kvm/handle_exit.c
> +++ b/arch/arm64/kvm/handle_exit.c
> @@ -186,6 +186,13 @@ int handle_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
> exit_handler = kvm_get_exit_handler(vcpu);
>
> return exit_handler(vcpu, run);
> + case ARM_EXCEPTION_HYP_GONE:
> + /*
> + * EL2 has been reset to the hyp-stub. This happens when a guest
> + * is pre-empted by kvm_reboot()'s shutdown call.
> + */
> + run->exit_reason = KVM_EXIT_FAIL_ENTRY;
> + return 0;
> default:
> kvm_pr_unimpl("Unsupported exception type: %d",
> exception_index);
to a separate patch (just before this one), I'd be quite happy.
So for this patch and the future one:
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
M.
--
Jazz is not dead. It just smells funny...
next prev parent reply other threads:[~2016-04-26 16:26 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-25 17:10 [PATCH v8 00/13] arm64: kernel: Add support for hibernate/suspend-to-disk James Morse
2016-04-25 17:10 ` [PATCH v8 01/13] arm64: Fold proc-macros.S into assembler.h James Morse
2016-04-25 17:10 ` [PATCH v8 02/13] arm64: Cleanup SCTLR flags James Morse
2016-04-25 17:10 ` [PATCH v8 03/13] arm64: kvm: Move lr save/restore from do_el2_call into EL1 James Morse
2016-04-25 17:10 ` [PATCH v8 04/13] arm64: hyp/kvm: Make hyp-stub extensible James Morse
2016-04-25 17:10 ` [PATCH v8 05/13] arm64: kvm: allows kvm cpu hotplug James Morse
2016-04-26 16:26 ` Marc Zyngier [this message]
2016-04-25 17:10 ` [PATCH v8 06/13] arm64: kernel: Rework finisher callback out of __cpu_suspend_enter() James Morse
2016-04-26 10:44 ` Catalin Marinas
2016-04-25 17:10 ` [PATCH v8 07/13] arm64: Change cpu_resume() to enable mmu early then access sleep_sp by va James Morse
2016-04-25 17:10 ` [PATCH v8 08/13] arm64: kernel: Include _AC definition in page.h James Morse
2016-04-25 17:10 ` [PATCH v8 09/13] arm64: Promote KERNEL_START/KERNEL_END definitions to a header file James Morse
2016-04-25 17:10 ` [PATCH v8 10/13] arm64: Add new asm macro copy_page James Morse
2016-04-25 17:10 ` [PATCH v8 11/13] PM / Hibernate: Call flush_icache_range() on pages restored in-place James Morse
2016-04-25 17:10 ` [PATCH v8 12/13] arm64: kernel: Add support for hibernate/suspend-to-disk James Morse
2016-04-26 14:39 ` Catalin Marinas
2016-04-25 17:10 ` [PATCH v8 13/13] arm64: hibernate: Refuse to hibernate if the boot cpu is offline James Morse
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