Commit e21a4f3a authored by Christoffer Dall's avatar Christoffer Dall Committed by Marc Zyngier

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: 9b062471 ("KVM: Move vcpu_load to arch-specific kvm_arch_vcpu_ioctl")
Reviewed-by: default avatarJulien Grall <julien.grall@arm.com>
Reviewed-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
Reviewed-by: default avatarAndrew Jones <drjones@redhat.com>
Signed-off-by: default avatarChristoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
parent 62b06f8f
...@@ -363,8 +363,6 @@ int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu, ...@@ -363,8 +363,6 @@ int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu,
{ {
int ret = 0; int ret = 0;
vcpu_load(vcpu);
trace_kvm_set_guest_debug(vcpu, dbg->control); trace_kvm_set_guest_debug(vcpu, dbg->control);
if (dbg->control & ~KVM_GUESTDBG_VALID_MASK) { if (dbg->control & ~KVM_GUESTDBG_VALID_MASK) {
...@@ -386,7 +384,6 @@ int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu, ...@@ -386,7 +384,6 @@ int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu,
} }
out: out:
vcpu_put(vcpu);
return ret; return ret;
} }
......
...@@ -384,14 +384,11 @@ static void vcpu_power_off(struct kvm_vcpu *vcpu) ...@@ -384,14 +384,11 @@ static void vcpu_power_off(struct kvm_vcpu *vcpu)
int kvm_arch_vcpu_ioctl_get_mpstate(struct kvm_vcpu *vcpu, int kvm_arch_vcpu_ioctl_get_mpstate(struct kvm_vcpu *vcpu,
struct kvm_mp_state *mp_state) struct kvm_mp_state *mp_state)
{ {
vcpu_load(vcpu);
if (vcpu->arch.power_off) if (vcpu->arch.power_off)
mp_state->mp_state = KVM_MP_STATE_STOPPED; mp_state->mp_state = KVM_MP_STATE_STOPPED;
else else
mp_state->mp_state = KVM_MP_STATE_RUNNABLE; mp_state->mp_state = KVM_MP_STATE_RUNNABLE;
vcpu_put(vcpu);
return 0; return 0;
} }
...@@ -400,8 +397,6 @@ int kvm_arch_vcpu_ioctl_set_mpstate(struct kvm_vcpu *vcpu, ...@@ -400,8 +397,6 @@ int kvm_arch_vcpu_ioctl_set_mpstate(struct kvm_vcpu *vcpu,
{ {
int ret = 0; int ret = 0;
vcpu_load(vcpu);
switch (mp_state->mp_state) { switch (mp_state->mp_state) {
case KVM_MP_STATE_RUNNABLE: case KVM_MP_STATE_RUNNABLE:
vcpu->arch.power_off = false; vcpu->arch.power_off = false;
...@@ -413,7 +408,6 @@ int kvm_arch_vcpu_ioctl_set_mpstate(struct kvm_vcpu *vcpu, ...@@ -413,7 +408,6 @@ int kvm_arch_vcpu_ioctl_set_mpstate(struct kvm_vcpu *vcpu,
ret = -EINVAL; ret = -EINVAL;
} }
vcpu_put(vcpu);
return ret; return ret;
} }
...@@ -1036,8 +1030,6 @@ long kvm_arch_vcpu_ioctl(struct file *filp, ...@@ -1036,8 +1030,6 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
struct kvm_device_attr attr; struct kvm_device_attr attr;
long r; long r;
vcpu_load(vcpu);
switch (ioctl) { switch (ioctl) {
case KVM_ARM_VCPU_INIT: { case KVM_ARM_VCPU_INIT: {
struct kvm_vcpu_init init; struct kvm_vcpu_init init;
...@@ -1114,7 +1106,6 @@ long kvm_arch_vcpu_ioctl(struct file *filp, ...@@ -1114,7 +1106,6 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
r = -EINVAL; r = -EINVAL;
} }
vcpu_put(vcpu);
return r; return r;
} }
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment