diff options
| author | James Morse <james.morse@arm.com> | 2016-04-27 19:47:04 +0300 |
|---|---|---|
| committer | Will Deacon <will.deacon@arm.com> | 2016-04-28 14:05:46 +0300 |
| commit | c94b0cf28281d483c8b43b4874fcb7ab14ade1b1 (patch) | |
| tree | 9a1b36f51a6dc5d2886f36454a1e3ac63eae640f /arch | |
| parent | ad72e59ff2bad55f6b9e7ac1fe5d824831ea2550 (diff) | |
| download | linux-c94b0cf28281d483c8b43b4874fcb7ab14ade1b1.tar.xz | |
arm64: hyp/kvm: Make hyp-stub reject kvm_call_hyp()
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>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arm64/include/asm/kvm_asm.h | 2 | ||||
| -rw-r--r-- | arch/arm64/kernel/hyp-stub.S | 5 | ||||
| -rw-r--r-- | arch/arm64/kvm/handle_exit.c | 7 |
3 files changed, 12 insertions, 2 deletions
diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h index eb7490d232a0..dbfbc5fb5d35 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); |