From e21a4f3a930cda6e4902cb5b3213365e5ff3ce7c Mon Sep 17 00:00:00 2001 From: Christoffer Dall Date: Tue, 27 Feb 2018 12:33:50 +0100 Subject: KVM: arm/arm64: Avoid vcpu_load for other vcpu ioctls than KVM_RUN Calling vcpu_load() registers preempt notifiers for this vcpu and calls kvm_arch_vcpu_load(). The latter will soon be doing a lot of heavy lifting on arm/arm64 and will try to do things such as enabling the virtual timer and setting us up to handle interrupts from the timer hardware. Loading state onto hardware registers and enabling hardware to signal interrupts can be problematic when we're not actually about to run the VCPU, because it makes it difficult to establish the right context when handling interrupts from the timer, and it makes the register access code difficult to reason about. Luckily, now when we call vcpu_load in each ioctl implementation, we can simply remove the call from the non-KVM_RUN vcpu ioctls, and our kvm_arch_vcpu_load() is only used for loading vcpu content to the physical CPU when we're actually going to run the vcpu. Cc: stable@vger.kernel.org Fixes: 9b062471e52a ("KVM: Move vcpu_load to arch-specific kvm_arch_vcpu_ioctl") Reviewed-by: Julien Grall Reviewed-by: Marc Zyngier Reviewed-by: Andrew Jones Signed-off-by: Christoffer Dall Signed-off-by: Marc Zyngier --- arch/arm64/kvm/guest.c | 3 --- 1 file changed, 3 deletions(-) (limited to 'arch/arm64') diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c index d7e3299a7734..959e50d2588c 100644 --- a/arch/arm64/kvm/guest.c +++ b/arch/arm64/kvm/guest.c @@ -363,8 +363,6 @@ int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu, { int ret = 0; - vcpu_load(vcpu); - trace_kvm_set_guest_debug(vcpu, dbg->control); if (dbg->control & ~KVM_GUESTDBG_VALID_MASK) { @@ -386,7 +384,6 @@ int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu, } out: - vcpu_put(vcpu); return ret; } -- cgit v1.2.3