* [PULL 72/79] KVM: arm/arm64: Support arch timers with a userspace gic
From: Christoffer Dall @ 2017-04-23 17:09 UTC (permalink / raw)
To: linux-arm-kernel
In-Reply-To: <20170423170929.27334-1-cdall@linaro.org>
From: Alexander Graf <agraf@suse.de>
If you're running with a userspace gic or other interrupt controller
(that is no vgic in the kernel), then you have so far not been able to
use the architected timers, because the output of the architected
timers, which are driven inside the kernel, was a kernel-only construct
between the arch timer code and the vgic.
This patch implements the new KVM_CAP_ARM_USER_IRQ feature, where we use a
side channel on the kvm_run structure, run->s.regs.device_irq_level, to
always notify userspace of the timer output levels when using a userspace
irqchip.
This works by ensuring that before we enter the guest, if the timer
output level has changed compared to what we last told userspace, we
don't enter the guest, but instead return to userspace to notify it of
the new level. If we are exiting, because of an MMIO for example, and
the level changed at the same time, the value is also updated and
userspace can sample the line as it needs. This is nicely achieved
simply always updating the timer_irq_level field after the main run
loop.
Note that the kvm_timer_update_irq trace event is changed to show the
host IRQ number for the timer instead of the guest IRQ number, because
the kernel no longer know which IRQ userspace wires up the timer signal
to.
Also note that this patch implements all required functionality but does
not yet advertise the capability.
Reviewed-by: Alexander Graf <agraf@suse.de>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
---
arch/arm/kvm/arm.c | 18 +++----
include/kvm/arm_arch_timer.h | 2 +
virt/kvm/arm/arch_timer.c | 122 +++++++++++++++++++++++++++++++++++--------
3 files changed, 110 insertions(+), 32 deletions(-)
diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index c378502..ac6e57b 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -515,13 +515,7 @@ static int kvm_vcpu_first_run_init(struct kvm_vcpu *vcpu)
return ret;
}
- /*
- * Enable the arch timers only if we have an in-kernel VGIC
- * and it has been properly initialized, since we cannot handle
- * interrupts from the virtual timer with a userspace gic.
- */
- if (irqchip_in_kernel(kvm) && vgic_initialized(kvm))
- ret = kvm_timer_enable(vcpu);
+ ret = kvm_timer_enable(vcpu);
return ret;
}
@@ -640,9 +634,12 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
local_irq_disable();
/*
- * Re-check atomic conditions
+ * If we have a singal pending, or need to notify a userspace
+ * irqchip about timer level changes, then we exit (and update
+ * the timer level state in kvm_timer_update_run below).
*/
- if (signal_pending(current)) {
+ if (signal_pending(current) ||
+ kvm_timer_should_notify_user(vcpu)) {
ret = -EINTR;
run->exit_reason = KVM_EXIT_INTR;
}
@@ -714,6 +711,9 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
ret = handle_exit(vcpu, run, ret);
}
+ /* Tell userspace about in-kernel device output levels */
+ kvm_timer_update_run(vcpu);
+
if (vcpu->sigset_active)
sigprocmask(SIG_SETMASK, &sigsaved, NULL);
return ret;
diff --git a/include/kvm/arm_arch_timer.h b/include/kvm/arm_arch_timer.h
index fe797d6..295584f 100644
--- a/include/kvm/arm_arch_timer.h
+++ b/include/kvm/arm_arch_timer.h
@@ -63,6 +63,8 @@ int kvm_timer_vcpu_reset(struct kvm_vcpu *vcpu,
void kvm_timer_vcpu_init(struct kvm_vcpu *vcpu);
void kvm_timer_flush_hwstate(struct kvm_vcpu *vcpu);
void kvm_timer_sync_hwstate(struct kvm_vcpu *vcpu);
+bool kvm_timer_should_notify_user(struct kvm_vcpu *vcpu);
+void kvm_timer_update_run(struct kvm_vcpu *vcpu);
void kvm_timer_vcpu_terminate(struct kvm_vcpu *vcpu);
u64 kvm_arm_timer_get_reg(struct kvm_vcpu *, u64 regid);
diff --git a/virt/kvm/arm/arch_timer.c b/virt/kvm/arm/arch_timer.c
index 363f0d2..5dc2167 100644
--- a/virt/kvm/arm/arch_timer.c
+++ b/virt/kvm/arm/arch_timer.c
@@ -184,6 +184,27 @@ bool kvm_timer_should_fire(struct arch_timer_context *timer_ctx)
return cval <= now;
}
+/*
+ * Reflect the timer output level into the kvm_run structure
+ */
+void kvm_timer_update_run(struct kvm_vcpu *vcpu)
+{
+ struct arch_timer_context *vtimer = vcpu_vtimer(vcpu);
+ struct arch_timer_context *ptimer = vcpu_ptimer(vcpu);
+ struct kvm_sync_regs *regs = &vcpu->run->s.regs;
+
+ if (likely(irqchip_in_kernel(vcpu->kvm)))
+ return;
+
+ /* Populate the device bitmap with the timer states */
+ regs->device_irq_level &= ~(KVM_ARM_DEV_EL1_VTIMER |
+ KVM_ARM_DEV_EL1_PTIMER);
+ if (vtimer->irq.level)
+ regs->device_irq_level |= KVM_ARM_DEV_EL1_VTIMER;
+ if (ptimer->irq.level)
+ regs->device_irq_level |= KVM_ARM_DEV_EL1_PTIMER;
+}
+
static void kvm_timer_update_irq(struct kvm_vcpu *vcpu, bool new_level,
struct arch_timer_context *timer_ctx)
{
@@ -194,9 +215,12 @@ static void kvm_timer_update_irq(struct kvm_vcpu *vcpu, bool new_level,
trace_kvm_timer_update_irq(vcpu->vcpu_id, timer_ctx->irq.irq,
timer_ctx->irq.level);
- ret = kvm_vgic_inject_irq(vcpu->kvm, vcpu->vcpu_id, timer_ctx->irq.irq,
- timer_ctx->irq.level);
- WARN_ON(ret);
+ if (likely(irqchip_in_kernel(vcpu->kvm))) {
+ ret = kvm_vgic_inject_irq(vcpu->kvm, vcpu->vcpu_id,
+ timer_ctx->irq.irq,
+ timer_ctx->irq.level);
+ WARN_ON(ret);
+ }
}
/*
@@ -215,7 +239,7 @@ static void kvm_timer_update_state(struct kvm_vcpu *vcpu)
* because the guest would never see the interrupt. Instead wait
* until we call this function from kvm_timer_flush_hwstate.
*/
- if (!timer->enabled)
+ if (unlikely(!timer->enabled))
return;
if (kvm_timer_should_fire(vtimer) != vtimer->irq.level)
@@ -282,28 +306,12 @@ void kvm_timer_unschedule(struct kvm_vcpu *vcpu)
timer_disarm(timer);
}
-/**
- * kvm_timer_flush_hwstate - prepare to move the virt timer to the cpu
- * @vcpu: The vcpu pointer
- *
- * Check if the virtual timer has expired while we were running in the host,
- * and inject an interrupt if that was the case.
- */
-void kvm_timer_flush_hwstate(struct kvm_vcpu *vcpu)
+static void kvm_timer_flush_hwstate_vgic(struct kvm_vcpu *vcpu)
{
- struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
struct arch_timer_context *vtimer = vcpu_vtimer(vcpu);
bool phys_active;
int ret;
- if (unlikely(!timer->enabled))
- return;
-
- kvm_timer_update_state(vcpu);
-
- /* Set the background timer for the physical timer emulation. */
- kvm_timer_emulate(vcpu, vcpu_ptimer(vcpu));
-
/*
* If we enter the guest with the virtual input level to the VGIC
* asserted, then we have already told the VGIC what we need to, and
@@ -355,11 +363,72 @@ void kvm_timer_flush_hwstate(struct kvm_vcpu *vcpu)
vtimer->active_cleared_last = !phys_active;
}
+bool kvm_timer_should_notify_user(struct kvm_vcpu *vcpu)
+{
+ struct arch_timer_context *vtimer = vcpu_vtimer(vcpu);
+ struct arch_timer_context *ptimer = vcpu_ptimer(vcpu);
+ struct kvm_sync_regs *sregs = &vcpu->run->s.regs;
+ bool vlevel, plevel;
+
+ if (likely(irqchip_in_kernel(vcpu->kvm)))
+ return false;
+
+ vlevel = sregs->device_irq_level & KVM_ARM_DEV_EL1_VTIMER;
+ plevel = sregs->device_irq_level & KVM_ARM_DEV_EL1_PTIMER;
+
+ return vtimer->irq.level != vlevel ||
+ ptimer->irq.level != plevel;
+}
+
+static void kvm_timer_flush_hwstate_user(struct kvm_vcpu *vcpu)
+{
+ struct arch_timer_context *vtimer = vcpu_vtimer(vcpu);
+
+ /*
+ * To prevent continuously exiting from the guest, we mask the
+ * physical interrupt such that the guest can make forward progress.
+ * Once we detect the output level being deasserted, we unmask the
+ * interrupt again so that we exit from the guest when the timer
+ * fires.
+ */
+ if (vtimer->irq.level)
+ disable_percpu_irq(host_vtimer_irq);
+ else
+ enable_percpu_irq(host_vtimer_irq, 0);
+}
+
+/**
+ * kvm_timer_flush_hwstate - prepare timers before running the vcpu
+ * @vcpu: The vcpu pointer
+ *
+ * Check if the virtual timer has expired while we were running in the host,
+ * and inject an interrupt if that was the case, making sure the timer is
+ * masked or disabled on the host so that we keep executing. Also schedule a
+ * software timer for the physical timer if it is enabled.
+ */
+void kvm_timer_flush_hwstate(struct kvm_vcpu *vcpu)
+{
+ struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
+
+ if (unlikely(!timer->enabled))
+ return;
+
+ kvm_timer_update_state(vcpu);
+
+ /* Set the background timer for the physical timer emulation. */
+ kvm_timer_emulate(vcpu, vcpu_ptimer(vcpu));
+
+ if (unlikely(!irqchip_in_kernel(vcpu->kvm)))
+ kvm_timer_flush_hwstate_user(vcpu);
+ else
+ kvm_timer_flush_hwstate_vgic(vcpu);
+}
+
/**
* kvm_timer_sync_hwstate - sync timer state from cpu
* @vcpu: The vcpu pointer
*
- * Check if the virtual timer has expired while we were running in the guest,
+ * Check if any of the timers have expired while we were running in the guest,
* and inject an interrupt if that was the case.
*/
void kvm_timer_sync_hwstate(struct kvm_vcpu *vcpu)
@@ -559,6 +628,13 @@ int kvm_timer_enable(struct kvm_vcpu *vcpu)
if (timer->enabled)
return 0;
+ /* Without a VGIC we do not map virtual IRQs to physical IRQs */
+ if (!irqchip_in_kernel(vcpu->kvm))
+ goto no_vgic;
+
+ if (!vgic_initialized(vcpu->kvm))
+ return -ENODEV;
+
/*
* Find the physical IRQ number corresponding to the host_vtimer_irq
*/
@@ -582,8 +658,8 @@ int kvm_timer_enable(struct kvm_vcpu *vcpu)
if (ret)
return ret;
+no_vgic:
timer->enabled = 1;
-
return 0;
}
--
2.9.0
^ permalink raw reply related
* [PULL 71/79] KVM: arm/arm64: Add ARM user space interrupt signaling ABI
From: Christoffer Dall @ 2017-04-23 17:09 UTC (permalink / raw)
To: linux-arm-kernel
In-Reply-To: <20170423170929.27334-1-cdall@linaro.org>
From: Alexander Graf <agraf@suse.de>
We have 2 modes for dealing with interrupts in the ARM world. We can
either handle them all using hardware acceleration through the vgic or
we can emulate a gic in user space and only drive CPU IRQ pins from
there.
Unfortunately, when driving IRQs from user space, we never tell user
space about events from devices emulated inside the kernel, which may
result in interrupt line state changes, so we lose out on for example
timer and PMU events if we run with user space gic emulation.
Define an ABI to publish such device output levels to userspace.
Reviewed-by: Alexander Graf <agraf@suse.de>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
Documentation/virtual/kvm/api.txt | 42 +++++++++++++++++++++++++++++++++++++++
arch/arm/include/uapi/asm/kvm.h | 2 ++
arch/arm64/include/uapi/asm/kvm.h | 2 ++
include/uapi/linux/kvm.h | 8 ++++++++
4 files changed, 54 insertions(+)
diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index 3c248f7..3b4e76e 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -4147,3 +4147,45 @@ This capability, if KVM_CHECK_EXTENSION indicates that it is
available, means that that the kernel can support guests using the
hashed page table MMU defined in Power ISA V3.00 (as implemented in
the POWER9 processor), including in-memory segment tables.
+
+
+8.5 KVM_CAP_ARM_USER_IRQ
+
+Architectures: arm, arm64
+This capability, if KVM_CHECK_EXTENSION indicates that it is available, means
+that if userspace creates a VM without an in-kernel interrupt controller, it
+will be notified of changes to the output level of in-kernel emulated devices,
+which can generate virtual interrupts, presented to the VM.
+For such VMs, on every return to userspace, the kernel
+updates the vcpu's run->s.regs.device_irq_level field to represent the actual
+output level of the device.
+
+Whenever kvm detects a change in the device output level, kvm guarantees at
+least one return to userspace before running the VM. This exit could either
+be a KVM_EXIT_INTR or any other exit event, like KVM_EXIT_MMIO. This way,
+userspace can always sample the device output level and re-compute the state of
+the userspace interrupt controller. Userspace should always check the state
+of run->s.regs.device_irq_level on every kvm exit.
+The value in run->s.regs.device_irq_level can represent both level and edge
+triggered interrupt signals, depending on the device. Edge triggered interrupt
+signals will exit to userspace with the bit in run->s.regs.device_irq_level
+set exactly once per edge signal.
+
+The field run->s.regs.device_irq_level is available independent of
+run->kvm_valid_regs or run->kvm_dirty_regs bits.
+
+If KVM_CAP_ARM_USER_IRQ is supported, the KVM_CHECK_EXTENSION ioctl returns a
+number larger than 0 indicating the version of this capability is implemented
+and thereby which bits in in run->s.regs.device_irq_level can signal values.
+
+Currently the following bits are defined for the device_irq_level bitmap:
+
+ KVM_CAP_ARM_USER_IRQ >= 1:
+
+ KVM_ARM_DEV_EL1_VTIMER - EL1 virtual timer
+ KVM_ARM_DEV_EL1_PTIMER - EL1 physical timer
+ KVM_ARM_DEV_PMU - ARM PMU overflow interrupt signal
+
+Future versions of kvm may implement additional events. These will get
+indicated by returning a higher number from KVM_CHECK_EXTENSION and will be
+listed above.
diff --git a/arch/arm/include/uapi/asm/kvm.h b/arch/arm/include/uapi/asm/kvm.h
index 6ebd3e6..a5838d6 100644
--- a/arch/arm/include/uapi/asm/kvm.h
+++ b/arch/arm/include/uapi/asm/kvm.h
@@ -114,6 +114,8 @@ struct kvm_debug_exit_arch {
};
struct kvm_sync_regs {
+ /* Used with KVM_CAP_ARM_USER_IRQ */
+ __u64 device_irq_level;
};
struct kvm_arch_memory_slot {
diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
index c286035..cd6bea4 100644
--- a/arch/arm64/include/uapi/asm/kvm.h
+++ b/arch/arm64/include/uapi/asm/kvm.h
@@ -143,6 +143,8 @@ struct kvm_debug_exit_arch {
#define KVM_GUESTDBG_USE_HW (1 << 17)
struct kvm_sync_regs {
+ /* Used with KVM_CAP_ARM_USER_IRQ */
+ __u64 device_irq_level;
};
struct kvm_arch_memory_slot {
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index f51d508..6d6b9b2 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -883,6 +883,7 @@ struct kvm_ppc_resize_hpt {
#define KVM_CAP_PPC_MMU_RADIX 134
#define KVM_CAP_PPC_MMU_HASH_V3 135
#define KVM_CAP_IMMEDIATE_EXIT 136
+#define KVM_CAP_ARM_USER_IRQ 137
#ifdef KVM_CAP_IRQ_ROUTING
@@ -1354,4 +1355,11 @@ struct kvm_assigned_msix_entry {
#define KVM_X2APIC_API_USE_32BIT_IDS (1ULL << 0)
#define KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK (1ULL << 1)
+/* Available with KVM_CAP_ARM_USER_IRQ */
+
+/* Bits for run->s.regs.device_irq_level */
+#define KVM_ARM_DEV_EL1_VTIMER (1 << 0)
+#define KVM_ARM_DEV_EL1_PTIMER (1 << 1)
+#define KVM_ARM_DEV_PMU (1 << 2)
+
#endif /* __LINUX_KVM_H */
--
2.9.0
^ permalink raw reply related
* [PULL 70/79] KVM: arm/arm64: Cleanup the arch timer code's irqchip checking
From: Christoffer Dall @ 2017-04-23 17:09 UTC (permalink / raw)
To: linux-arm-kernel
In-Reply-To: <20170423170929.27334-1-cdall@linaro.org>
From: Christoffer Dall <christoffer.dall@linaro.org>
Currently we check if we have an in-kernel irqchip and if the vgic was
properly implemented several places in the arch timer code. But, we
already predicate our enablement of the arm timers on having a valid
and initialized gic, so we can simply check if the timers are enabled or
not.
This also gets rid of the ugly "error that's not an error but used to
signal that the timer shouldn't poke the gic" construct we have.
Reviewed-by: Alexander Graf <agraf@suse.de>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
---
virt/kvm/arm/arch_timer.c | 15 +++++++--------
1 file changed, 7 insertions(+), 8 deletions(-)
diff --git a/virt/kvm/arm/arch_timer.c b/virt/kvm/arm/arch_timer.c
index 35d7100..363f0d2 100644
--- a/virt/kvm/arm/arch_timer.c
+++ b/virt/kvm/arm/arch_timer.c
@@ -189,8 +189,6 @@ static void kvm_timer_update_irq(struct kvm_vcpu *vcpu, bool new_level,
{
int ret;
- BUG_ON(!vgic_initialized(vcpu->kvm));
-
timer_ctx->active_cleared_last = false;
timer_ctx->irq.level = new_level;
trace_kvm_timer_update_irq(vcpu->vcpu_id, timer_ctx->irq.irq,
@@ -205,7 +203,7 @@ static void kvm_timer_update_irq(struct kvm_vcpu *vcpu, bool new_level,
* Check if there was a change in the timer state (should we raise or lower
* the line level to the GIC).
*/
-static int kvm_timer_update_state(struct kvm_vcpu *vcpu)
+static void kvm_timer_update_state(struct kvm_vcpu *vcpu)
{
struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
struct arch_timer_context *vtimer = vcpu_vtimer(vcpu);
@@ -217,16 +215,14 @@ static int kvm_timer_update_state(struct kvm_vcpu *vcpu)
* because the guest would never see the interrupt. Instead wait
* until we call this function from kvm_timer_flush_hwstate.
*/
- if (!vgic_initialized(vcpu->kvm) || !timer->enabled)
- return -ENODEV;
+ if (!timer->enabled)
+ return;
if (kvm_timer_should_fire(vtimer) != vtimer->irq.level)
kvm_timer_update_irq(vcpu, !vtimer->irq.level, vtimer);
if (kvm_timer_should_fire(ptimer) != ptimer->irq.level)
kvm_timer_update_irq(vcpu, !ptimer->irq.level, ptimer);
-
- return 0;
}
/* Schedule the background timer for the emulated timer. */
@@ -295,13 +291,16 @@ void kvm_timer_unschedule(struct kvm_vcpu *vcpu)
*/
void kvm_timer_flush_hwstate(struct kvm_vcpu *vcpu)
{
+ struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
struct arch_timer_context *vtimer = vcpu_vtimer(vcpu);
bool phys_active;
int ret;
- if (kvm_timer_update_state(vcpu))
+ if (unlikely(!timer->enabled))
return;
+ kvm_timer_update_state(vcpu);
+
/* Set the background timer for the physical timer emulation. */
kvm_timer_emulate(vcpu, vcpu_ptimer(vcpu));
--
2.9.0
^ permalink raw reply related
* [PULL 69/79] arm/arm64: Add hyp-stub API documentation
From: Christoffer Dall @ 2017-04-23 17:09 UTC (permalink / raw)
To: linux-arm-kernel
In-Reply-To: <20170423170929.27334-1-cdall@linaro.org>
From: Marc Zyngier <marc.zyngier@arm.com>
In order to help people understanding the hyp-stub API that exists
between the host kernel and the hypervisor mode (whether a hypervisor
has been installed or not), let's document said API.
As with any form of documentation, I expect it to become obsolete
and completely misleading within 20 minutes after having being merged.
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <cdall@linaro.org>
---
Documentation/virtual/kvm/arm/hyp-abi.txt | 53 +++++++++++++++++++++++++++++++
1 file changed, 53 insertions(+)
create mode 100644 Documentation/virtual/kvm/arm/hyp-abi.txt
diff --git a/Documentation/virtual/kvm/arm/hyp-abi.txt b/Documentation/virtual/kvm/arm/hyp-abi.txt
new file mode 100644
index 0000000..a20a0be
--- /dev/null
+++ b/Documentation/virtual/kvm/arm/hyp-abi.txt
@@ -0,0 +1,53 @@
+* Internal ABI between the kernel and HYP
+
+This file documents the interaction between the Linux kernel and the
+hypervisor layer when running Linux as a hypervisor (for example
+KVM). It doesn't cover the interaction of the kernel with the
+hypervisor when running as a guest (under Xen, KVM or any other
+hypervisor), or any hypervisor-specific interaction when the kernel is
+used as a host.
+
+On arm and arm64 (without VHE), the kernel doesn't run in hypervisor
+mode, but still needs to interact with it, allowing a built-in
+hypervisor to be either installed or torn down.
+
+In order to achieve this, the kernel must be booted at HYP (arm) or
+EL2 (arm64), allowing it to install a set of stubs before dropping to
+SVC/EL1. These stubs are accessible by using a 'hvc #0' instruction,
+and only act on individual CPUs.
+
+Unless specified otherwise, any built-in hypervisor must implement
+these functions (see arch/arm{,64}/include/asm/virt.h):
+
+* r0/x0 = HVC_SET_VECTORS
+ r1/x1 = vectors
+
+ Set HVBAR/VBAR_EL2 to 'vectors' to enable a hypervisor. 'vectors'
+ must be a physical address, and respect the alignment requirements
+ of the architecture. Only implemented by the initial stubs, not by
+ Linux hypervisors.
+
+* r0/x0 = HVC_RESET_VECTORS
+
+ Turn HYP/EL2 MMU off, and reset HVBAR/VBAR_EL2 to the initials
+ stubs' exception vector value. This effectively disables an existing
+ hypervisor.
+
+* r0/x0 = HVC_SOFT_RESTART
+ r1/x1 = restart address
+ x2 = x0's value when entering the next payload (arm64)
+ x3 = x1's value when entering the next payload (arm64)
+ x4 = x2's value when entering the next payload (arm64)
+
+ Mask all exceptions, disable the MMU, move the arguments into place
+ (arm64 only), and jump to the restart address while at HYP/EL2. This
+ hypercall is not expected to return to its caller.
+
+Any other value of r0/x0 triggers a hypervisor-specific handling,
+which is not documented here.
+
+The return value of a stub hypercall is held by r0/x0, and is 0 on
+success, and HVC_STUB_ERR on error. A stub hypercall is allowed to
+clobber any of the caller-saved registers (x0-x18 on arm64, r0-r3 and
+ip on arm). It is thus recommended to use a function call to perform
+the hypercall.
--
2.9.0
^ permalink raw reply related
* [PULL 68/79] ARM: hyp-stub: Zero r0 on successful stub handling
From: Christoffer Dall @ 2017-04-23 17:09 UTC (permalink / raw)
To: linux-arm-kernel
In-Reply-To: <20170423170929.27334-1-cdall@linaro.org>
From: Marc Zyngier <marc.zyngier@arm.com>
We now return HVC_STUB_ERR when a stub hypercall fails, but we
leave whatever was in r0 on success. Zeroing it on return seems
like a good idea.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <cdall@linaro.org>
---
arch/arm/kernel/hyp-stub.S | 2 ++
arch/arm/kvm/init.S | 2 ++
2 files changed, 4 insertions(+)
diff --git a/arch/arm/kernel/hyp-stub.S b/arch/arm/kernel/hyp-stub.S
index 918c64f..d8523cc 100644
--- a/arch/arm/kernel/hyp-stub.S
+++ b/arch/arm/kernel/hyp-stub.S
@@ -215,8 +215,10 @@ __hyp_stub_do_trap:
beq __hyp_stub_exit
ldr r0, =HVC_STUB_ERR
+ __ERET
__hyp_stub_exit:
+ mov r0, #0
__ERET
ENDPROC(__hyp_stub_do_trap)
diff --git a/arch/arm/kvm/init.S b/arch/arm/kvm/init.S
index 87bcd7a..570ed4a 100644
--- a/arch/arm/kvm/init.S
+++ b/arch/arm/kvm/init.S
@@ -155,8 +155,10 @@ reset:
b exit
1: ldr r0, =HVC_STUB_ERR
+ eret
exit:
+ mov r0, #0
eret
ENDPROC(__kvm_handle_stub_hvc)
--
2.9.0
^ permalink raw reply related
* [PULL 67/79] arm64: hyp-stub: Zero x0 on successful stub handling
From: Christoffer Dall @ 2017-04-23 17:09 UTC (permalink / raw)
To: linux-arm-kernel
In-Reply-To: <20170423170929.27334-1-cdall@linaro.org>
From: Marc Zyngier <marc.zyngier@arm.com>
We now return HVC_STUB_ERR when a stub hypercall fails, but we
leave whatever was in x0 on success. Zeroing it on return seems
like a good idea.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <cdall@linaro.org>
---
arch/arm64/kernel/hyp-stub.S | 4 +++-
arch/arm64/kvm/hyp-init.S | 6 +++---
2 files changed, 6 insertions(+), 4 deletions(-)
diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S
index d55604d..e1261fb 100644
--- a/arch/arm64/kernel/hyp-stub.S
+++ b/arch/arm64/kernel/hyp-stub.S
@@ -73,8 +73,10 @@ el1_sync:
/* Someone called kvm_call_hyp() against the hyp-stub... */
ldr x0, =HVC_STUB_ERR
+ eret
-9: eret
+9: mov x0, xzr
+ eret
ENDPROC(el1_sync)
.macro invalid_vector label
diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S
index 3734e63..839425c 100644
--- a/arch/arm64/kvm/hyp-init.S
+++ b/arch/arm64/kvm/hyp-init.S
@@ -154,13 +154,13 @@ reset:
/* Install stub vectors */
adr_l x5, __hyp_stub_vectors
msr vbar_el2, x5
- b exit
+ mov x0, xzr
+ eret
1: /* Bad stub call */
ldr x0, =HVC_STUB_ERR
-
-exit:
eret
+
ENDPROC(__kvm_handle_stub_hvc)
.ltorg
--
2.9.0
^ permalink raw reply related
* [PULL 66/79] arm64: hyp-stub/KVM: Kill __hyp_get_vectors
From: Christoffer Dall @ 2017-04-23 17:09 UTC (permalink / raw)
To: linux-arm-kernel
In-Reply-To: <20170423170929.27334-1-cdall@linaro.org>
From: Marc Zyngier <marc.zyngier@arm.com>
Nobody is using __hyp_get_vectors anymore, so let's remove both
implementations (hyp-stub and KVM).
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <cdall@linaro.org>
---
arch/arm64/include/asm/virt.h | 12 ++++--------
arch/arm64/kernel/hyp-stub.S | 13 +------------
arch/arm64/kvm/hyp-init.S | 7 +------
arch/arm64/kvm/hyp.S | 2 +-
4 files changed, 7 insertions(+), 27 deletions(-)
diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h
index 435514c..c5f8944 100644
--- a/arch/arm64/include/asm/virt.h
+++ b/arch/arm64/include/asm/virt.h
@@ -29,28 +29,25 @@
* indirection of a function call (as implemented in hyp-stub.S).
*/
-/* HVC_GET_VECTORS - Return the value of the vbar_el2 register. */
-#define HVC_GET_VECTORS 0
-
/*
* HVC_SET_VECTORS - Set the value of the vbar_el2 register.
*
* @x1: Physical address of the new vector table.
*/
-#define HVC_SET_VECTORS 1
+#define HVC_SET_VECTORS 0
/*
* HVC_SOFT_RESTART - CPU soft reset, used by the cpu_soft_restart routine.
*/
-#define HVC_SOFT_RESTART 2
+#define HVC_SOFT_RESTART 1
/*
* HVC_RESET_VECTORS - Restore the vectors to the original HYP stubs
*/
-#define HVC_RESET_VECTORS 3
+#define HVC_RESET_VECTORS 2
/* Max number of HYP stub hypercalls */
-#define HVC_STUB_HCALL_NR 4
+#define HVC_STUB_HCALL_NR 3
/* Error returned when an invalid stub number is passed into x0 */
#define HVC_STUB_ERR 0xbadca11
@@ -77,7 +74,6 @@
extern u32 __boot_cpu_mode[2];
void __hyp_set_vectors(phys_addr_t phys_vector_base);
-phys_addr_t __hyp_get_vectors(void);
void __hyp_reset_vectors(void);
/* Reports the availability of HYP mode */
diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S
index 8226fd9..d55604d 100644
--- a/arch/arm64/kernel/hyp-stub.S
+++ b/arch/arm64/kernel/hyp-stub.S
@@ -55,12 +55,7 @@ ENDPROC(__hyp_stub_vectors)
.align 11
el1_sync:
- cmp x0, #HVC_GET_VECTORS
- b.ne 1f
- mrs x0, vbar_el2
- b 9f
-
-1: cmp x0, #HVC_SET_VECTORS
+ cmp x0, #HVC_SET_VECTORS
b.ne 2f
msr vbar_el2, x1
b 9f
@@ -118,12 +113,6 @@ ENDPROC(\label)
* initialisation entry point.
*/
-ENTRY(__hyp_get_vectors)
- mov x0, #HVC_GET_VECTORS
- hvc #0
- ret
-ENDPROC(__hyp_get_vectors)
-
ENTRY(__hyp_set_vectors)
mov x1, x0
mov x0, #HVC_SET_VECTORS
diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S
index 0ad34fd..3734e63 100644
--- a/arch/arm64/kvm/hyp-init.S
+++ b/arch/arm64/kvm/hyp-init.S
@@ -124,12 +124,7 @@ __do_hyp_init:
ENDPROC(__kvm_hyp_init)
ENTRY(__kvm_handle_stub_hvc)
- cmp x0, #HVC_GET_VECTORS
- b.ne 1f
- mrs x0, vbar_el2
- b exit
-
-1: cmp x0, #HVC_SOFT_RESTART
+ cmp x0, #HVC_SOFT_RESTART
b.ne 1f
/* This is where we're about to jump, staying at EL2 */
diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S
index f6f20b5..952f6cb 100644
--- a/arch/arm64/kvm/hyp.S
+++ b/arch/arm64/kvm/hyp.S
@@ -36,7 +36,7 @@
* passed in x0.
*
* A function pointer with a value less than 0xfff has a special meaning,
- * and is used to implement __hyp_get_vectors in the same way as in
+ * and is used to implement hyp stubs in the same way as in
* arch/arm64/kernel/hyp_stub.S.
*/
ENTRY(__kvm_call_hyp)
--
2.9.0
^ permalink raw reply related
* [PULL 65/79] ARM: hyp-stub/KVM: Kill __hyp_get_vectors
From: Christoffer Dall @ 2017-04-23 17:09 UTC (permalink / raw)
To: linux-arm-kernel
In-Reply-To: <20170423170929.27334-1-cdall@linaro.org>
From: Marc Zyngier <marc.zyngier@arm.com>
Nobody is using __hyp_get_vectors anymore, so let's remove both
implementations (hyp-stub and KVM).
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <cdall@linaro.org>
---
arch/arm/include/asm/virt.h | 10 ++++------
arch/arm/kernel/hyp-stub.S | 13 +------------
arch/arm/kvm/init.S | 7 +------
arch/arm/kvm/interrupts.S | 4 ----
4 files changed, 6 insertions(+), 28 deletions(-)
diff --git a/arch/arm/include/asm/virt.h b/arch/arm/include/asm/virt.h
index 663adc0..141144f 100644
--- a/arch/arm/include/asm/virt.h
+++ b/arch/arm/include/asm/virt.h
@@ -53,7 +53,6 @@ static inline void sync_boot_mode(void)
}
void __hyp_set_vectors(unsigned long phys_vector_base);
-unsigned long __hyp_get_vectors(void);
void __hyp_reset_vectors(void);
#else
#define __boot_cpu_mode (SVC_MODE)
@@ -99,12 +98,11 @@ extern char __hyp_text_end[];
/* Only assembly code should need those */
-#define HVC_GET_VECTORS 0
-#define HVC_SET_VECTORS 1
-#define HVC_SOFT_RESTART 2
-#define HVC_RESET_VECTORS 3
+#define HVC_SET_VECTORS 0
+#define HVC_SOFT_RESTART 1
+#define HVC_RESET_VECTORS 2
-#define HVC_STUB_HCALL_NR 4
+#define HVC_STUB_HCALL_NR 3
#endif /* __ASSEMBLY__ */
diff --git a/arch/arm/kernel/hyp-stub.S b/arch/arm/kernel/hyp-stub.S
index 675c50f..918c64f 100644
--- a/arch/arm/kernel/hyp-stub.S
+++ b/arch/arm/kernel/hyp-stub.S
@@ -202,12 +202,7 @@ ARM_BE8(orr r7, r7, #(1 << 25)) @ HSCTLR.EE
ENDPROC(__hyp_stub_install_secondary)
__hyp_stub_do_trap:
- teq r0, #HVC_GET_VECTORS
- bne 1f
- mrc p15, 4, r0, c12, c0, 0 @ get HVBAR
- b __hyp_stub_exit
-
-1: teq r0, #HVC_SET_VECTORS
+ teq r0, #HVC_SET_VECTORS
bne 1f
mcr p15, 4, r1, c12, c0, 0 @ set HVBAR
b __hyp_stub_exit
@@ -247,12 +242,6 @@ ENDPROC(__hyp_stub_do_trap)
* so you will need to set that to something sensible@the new hypervisor's
* initialisation entry point.
*/
-ENTRY(__hyp_get_vectors)
- mov r0, #HVC_GET_VECTORS
- __HVC(0)
- ret lr
-ENDPROC(__hyp_get_vectors)
-
ENTRY(__hyp_set_vectors)
mov r1, r0
mov r0, #HVC_SET_VECTORS
diff --git a/arch/arm/kvm/init.S b/arch/arm/kvm/init.S
index e53360d..87bcd7a 100644
--- a/arch/arm/kvm/init.S
+++ b/arch/arm/kvm/init.S
@@ -122,12 +122,7 @@ __do_hyp_init:
eret
ENTRY(__kvm_handle_stub_hvc)
- cmp r0, #HVC_GET_VECTORS
- bne 1f
- mrc p15, 4, r0, c12, c0, 0 @ get HVBAR
- b exit
-
-1: cmp r0, #HVC_SOFT_RESTART
+ cmp r0, #HVC_SOFT_RESTART
bne 1f
/* The target is expected in r1 */
diff --git a/arch/arm/kvm/interrupts.S b/arch/arm/kvm/interrupts.S
index b1bd316..80a1d6c 100644
--- a/arch/arm/kvm/interrupts.S
+++ b/arch/arm/kvm/interrupts.S
@@ -37,10 +37,6 @@
* in Hyp mode (see init_hyp_mode in arch/arm/kvm/arm.c). Return values are
* passed in r0 (strictly 32bit).
*
- * A function pointer with a value of 0xffffffff has a special meaning,
- * and is used to implement __hyp_get_vectors in the same way as in
- * arch/arm/kernel/hyp_stub.S.
- *
* The calling convention follows the standard AAPCS:
* r0 - r3: caller save
* r12: caller save
--
2.9.0
^ permalink raw reply related
* [PULL 64/79] ARM: decompressor: Remove __hyp_get_vectors usage
From: Christoffer Dall @ 2017-04-23 17:09 UTC (permalink / raw)
To: linux-arm-kernel
In-Reply-To: <20170423170929.27334-1-cdall@linaro.org>
From: Marc Zyngier <marc.zyngier@arm.com>
When the compressed image needs to be relocated to avoid being
overwritten by the decompression process, we need to relocate
the hyp vectors as well so that we can find them once the
decompression has taken effect.
For that, we perform the following calculation:
u32 v = __hyp_get_vectors();
v += offset;
__hyp_set_vectors(v);
But we're guaranteed that the initial value of v as returned by
__hyp_get_vectors is always __hyp_stub_vectors, because we have
just set it by calling __hyp_stub_install.
So let's remove the use of __hyp_get_vectors, and directly use
__hyp_stub_vectors instead.
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <cdall@linaro.org>
---
arch/arm/boot/compressed/head.S | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S
index 9150f97..7c711ba 100644
--- a/arch/arm/boot/compressed/head.S
+++ b/arch/arm/boot/compressed/head.S
@@ -422,7 +422,17 @@ dtb_check_done:
cmp r0, #HYP_MODE
bne 1f
- bl __hyp_get_vectors
+ /*
+ * Compute the address of the hyp vectors after relocation.
+ * This requires some arithmetic since we cannot directly
+ * reference __hyp_stub_vectors in a PC-relative way.
+ * Call __hyp_set_vectors with the new address so that we
+ * can HVC again after the copy.
+ */
+0: adr r0, 0b
+ movw r1, #:lower16:__hyp_stub_vectors - 0b
+ movt r1, #:upper16:__hyp_stub_vectors - 0b
+ add r0, r0, r1
sub r0, r0, r5
add r0, r0, r10
bl __hyp_set_vectors
--
2.9.0
^ permalink raw reply related
* [PULL 63/79] arm/arm64: KVM: Use HVC_RESET_VECTORS to reinit HYP mode
From: Christoffer Dall @ 2017-04-23 17:09 UTC (permalink / raw)
To: linux-arm-kernel
In-Reply-To: <20170423170929.27334-1-cdall@linaro.org>
From: Marc Zyngier <marc.zyngier@arm.com>
Instead of trying to compare the value given by __hyp_get_vectors(),
which doesn't offer any real guarantee to be the stub's address, use
HVC_RESET_VECTORS to make sure we're in a sane state to reinstall
KVM across PM events.
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <cdall@linaro.org>
---
arch/arm/kvm/arm.c | 24 +++++++++---------------
1 file changed, 9 insertions(+), 15 deletions(-)
diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index c8f4fa6..c378502 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -53,7 +53,6 @@ __asm__(".arch_extension virt");
static DEFINE_PER_CPU(unsigned long, kvm_arm_hyp_stack_page);
static kvm_cpu_context_t __percpu *kvm_host_cpu_state;
-static unsigned long hyp_default_vectors;
/* Per-CPU variable containing the currently running vcpu. */
static DEFINE_PER_CPU(struct kvm_vcpu *, kvm_arm_running_vcpu);
@@ -1113,8 +1112,16 @@ static void cpu_init_hyp_mode(void *dummy)
kvm_arm_init_debug();
}
+static void cpu_hyp_reset(void)
+{
+ if (!is_kernel_in_hyp_mode())
+ __hyp_reset_vectors();
+}
+
static void cpu_hyp_reinit(void)
{
+ cpu_hyp_reset();
+
if (is_kernel_in_hyp_mode()) {
/*
* __cpu_init_stage2() is safe to call even if the PM
@@ -1122,17 +1129,10 @@ static void cpu_hyp_reinit(void)
*/
__cpu_init_stage2();
} else {
- if (__hyp_get_vectors() == hyp_default_vectors)
- cpu_init_hyp_mode(NULL);
+ cpu_init_hyp_mode(NULL);
}
}
-static void cpu_hyp_reset(void)
-{
- if (!is_kernel_in_hyp_mode())
- __hyp_reset_vectors();
-}
-
static void _kvm_arch_hardware_enable(void *discard)
{
if (!__this_cpu_read(kvm_arm_hardware_enabled)) {
@@ -1316,12 +1316,6 @@ static int init_hyp_mode(void)
goto out_err;
/*
- * It is probably enough to obtain the default on one
- * CPU. It's unlikely to be different on the others.
- */
- hyp_default_vectors = __hyp_get_vectors();
-
- /*
* Allocate stack pages for Hypervisor-mode
*/
for_each_possible_cpu(cpu) {
--
2.9.0
^ permalink raw reply related
* [PULL 62/79] arm/arm64: KVM: Remove kvm_get_idmap_start
From: Christoffer Dall @ 2017-04-23 17:09 UTC (permalink / raw)
To: linux-arm-kernel
In-Reply-To: <20170423170929.27334-1-cdall@linaro.org>
From: Marc Zyngier <marc.zyngier@arm.com>
With __cpu_reset_hyp_mode having become fairly dumb, there is no
need for kvm_get_idmap_start anymore.
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <cdall@linaro.org>
---
arch/arm/include/asm/kvm_mmu.h | 1 -
arch/arm/kvm/mmu.c | 5 -----
arch/arm64/include/asm/kvm_mmu.h | 1 -
3 files changed, 7 deletions(-)
diff --git a/arch/arm/include/asm/kvm_mmu.h b/arch/arm/include/asm/kvm_mmu.h
index 95f38dc..fa6f217 100644
--- a/arch/arm/include/asm/kvm_mmu.h
+++ b/arch/arm/include/asm/kvm_mmu.h
@@ -56,7 +56,6 @@ void kvm_mmu_free_memory_caches(struct kvm_vcpu *vcpu);
phys_addr_t kvm_mmu_get_httbr(void);
phys_addr_t kvm_get_idmap_vector(void);
-phys_addr_t kvm_get_idmap_start(void);
int kvm_mmu_init(void);
void kvm_clear_hyp_idmap(void);
diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
index 69554bd..efb4335 100644
--- a/arch/arm/kvm/mmu.c
+++ b/arch/arm/kvm/mmu.c
@@ -1669,11 +1669,6 @@ phys_addr_t kvm_get_idmap_vector(void)
return hyp_idmap_vector;
}
-phys_addr_t kvm_get_idmap_start(void)
-{
- return hyp_idmap_start;
-}
-
static int kvm_map_idmap_text(pgd_t *pgd)
{
int err;
diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h
index ed12460..91d93a5 100644
--- a/arch/arm64/include/asm/kvm_mmu.h
+++ b/arch/arm64/include/asm/kvm_mmu.h
@@ -155,7 +155,6 @@ void kvm_mmu_free_memory_caches(struct kvm_vcpu *vcpu);
phys_addr_t kvm_mmu_get_httbr(void);
phys_addr_t kvm_get_idmap_vector(void);
-phys_addr_t kvm_get_idmap_start(void);
int kvm_mmu_init(void);
void kvm_clear_hyp_idmap(void);
--
2.9.0
^ permalink raw reply related
* [PULL 61/79] arm/arm64: KVM: Use __hyp_reset_vectors() directly
From: Christoffer Dall @ 2017-04-23 17:09 UTC (permalink / raw)
To: linux-arm-kernel
In-Reply-To: <20170423170929.27334-1-cdall@linaro.org>
From: Marc Zyngier <marc.zyngier@arm.com>
__cpu_reset_hyp_mode doesn't need to be passed any argument now,
as the hyp-stub implementations are self-contained, and is now
reduced to just calling __hyp_reset_vectors(). Let's drop the
wrapper and use the stub hypercall directly.
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <cdall@linaro.org>
---
arch/arm/include/asm/kvm_host.h | 6 ------
arch/arm/kvm/arm.c | 3 +--
arch/arm64/include/asm/kvm_host.h | 6 ------
3 files changed, 1 insertion(+), 14 deletions(-)
diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
index adea307..d488b88 100644
--- a/arch/arm/include/asm/kvm_host.h
+++ b/arch/arm/include/asm/kvm_host.h
@@ -270,12 +270,6 @@ static inline void __cpu_init_stage2(void)
kvm_call_hyp(__init_stage2_translation);
}
-static inline void __cpu_reset_hyp_mode(unsigned long vector_ptr,
- phys_addr_t phys_idmap_start)
-{
- __hyp_reset_vectors();
-}
-
static inline int kvm_arch_dev_ioctl_check_extension(struct kvm *kvm, long ext)
{
return 0;
diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index 46fd375..c8f4fa6 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -1130,8 +1130,7 @@ static void cpu_hyp_reinit(void)
static void cpu_hyp_reset(void)
{
if (!is_kernel_in_hyp_mode())
- __cpu_reset_hyp_mode(hyp_default_vectors,
- kvm_get_idmap_start());
+ __hyp_reset_vectors();
}
static void _kvm_arch_hardware_enable(void *discard)
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 0355dd1..578df18 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -362,12 +362,6 @@ static inline void __cpu_init_hyp_mode(phys_addr_t pgd_ptr,
__kvm_call_hyp((void *)pgd_ptr, hyp_stack_ptr, vector_ptr);
}
-static inline void __cpu_reset_hyp_mode(unsigned long vector_ptr,
- phys_addr_t phys_idmap_start)
-{
- __hyp_reset_vectors();
-}
-
static inline void kvm_arch_hardware_unsetup(void) {}
static inline void kvm_arch_sync_events(struct kvm *kvm) {}
static inline void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu) {}
--
2.9.0
^ permalink raw reply related
* [PULL 60/79] ARM: KVM: Gracefully handle hyp-stubs being restored from under our feet
From: Christoffer Dall @ 2017-04-23 17:09 UTC (permalink / raw)
To: linux-arm-kernel
In-Reply-To: <20170423170929.27334-1-cdall@linaro.org>
From: Marc Zyngier <marc.zyngier@arm.com>
Should kvm_reboot() be invoked while guest is running, an IPI
wil be issued, forcing the guest to exit and HYP being reset to
the stubs. We will then try to reenter the guest, only to get
an error (HVC_STUB_ERR).
This patch allows this case to be gracefully handled by exiting
the run loop.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <cdall@linaro.org>
---
arch/arm/include/asm/kvm_asm.h | 2 +-
arch/arm/kvm/handle_exit.c | 8 ++++++++
2 files changed, 9 insertions(+), 1 deletion(-)
diff --git a/arch/arm/include/asm/kvm_asm.h b/arch/arm/include/asm/kvm_asm.h
index eae11b3..14d68a4 100644
--- a/arch/arm/include/asm/kvm_asm.h
+++ b/arch/arm/include/asm/kvm_asm.h
@@ -33,7 +33,7 @@
#define ARM_EXCEPTION_IRQ 5
#define ARM_EXCEPTION_FIQ 6
#define ARM_EXCEPTION_HVC 7
-
+#define ARM_EXCEPTION_HYP_GONE HVC_STUB_ERR
/*
* The rr_lo_hi macro swaps a pair of registers depending on
* current endianness. It is used in conjunction with ldrd and strd
diff --git a/arch/arm/kvm/handle_exit.c b/arch/arm/kvm/handle_exit.c
index 96af65a..5fd7968 100644
--- a/arch/arm/kvm/handle_exit.c
+++ b/arch/arm/kvm/handle_exit.c
@@ -160,6 +160,14 @@ int handle_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
case ARM_EXCEPTION_DATA_ABORT:
kvm_inject_vabt(vcpu);
return 1;
+ case ARM_EXCEPTION_HYP_GONE:
+ /*
+ * HYP 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);
--
2.9.0
^ permalink raw reply related
* [PULL 59/79] ARM: KVM: Implement HVC_SOFT_RESTART in the init code
From: Christoffer Dall @ 2017-04-23 17:09 UTC (permalink / raw)
To: linux-arm-kernel
In-Reply-To: <20170423170929.27334-1-cdall@linaro.org>
From: Marc Zyngier <marc.zyngier@arm.com>
Another missing stub hypercall is HVC_SOFT_RESTART. It turns out
that it is pretty easy to implement in terms of HVC_RESET_VECTORS
(since it needs to turn the MMU off).
Tested-by: Keerthy <j-keerthy@ti.com>
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <cdall@linaro.org>
---
arch/arm/kvm/init.S | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/arch/arm/kvm/init.S b/arch/arm/kvm/init.S
index fb33609..e53360d 100644
--- a/arch/arm/kvm/init.S
+++ b/arch/arm/kvm/init.S
@@ -127,8 +127,22 @@ ENTRY(__kvm_handle_stub_hvc)
mrc p15, 4, r0, c12, c0, 0 @ get HVBAR
b exit
+1: cmp r0, #HVC_SOFT_RESTART
+ bne 1f
+
+ /* The target is expected in r1 */
+ msr ELR_hyp, r1
+ mrs r0, cpsr
+ bic r0, r0, #MODE_MASK
+ orr r0, r0, #HYP_MODE
+THUMB( orr r0, r0, #PSR_T_BIT )
+ msr spsr_cxsf, r0
+ b reset
+
1: cmp r0, #HVC_RESET_VECTORS
bne 1f
+
+reset:
/* We're now in idmap, disable MMU */
mrc p15, 4, r1, c1, c0, 0 @ HSCTLR
ldr r0, =(HSCTLR_M | HSCTLR_A | HSCTLR_C | HSCTLR_I)
--
2.9.0
^ permalink raw reply related
* [PULL 58/79] ARM: KVM: Convert __cpu_reset_hyp_mode to using __hyp_reset_vectors
From: Christoffer Dall @ 2017-04-23 17:09 UTC (permalink / raw)
To: linux-arm-kernel
In-Reply-To: <20170423170929.27334-1-cdall@linaro.org>
From: Marc Zyngier <marc.zyngier@arm.com>
We are now able to use the hyp stub to reset HYP mode. Time to
kiss __kvm_hyp_reset goodbye, and use __hyp_reset_vectors.
Tested-by: Keerthy <j-keerthy@ti.com>
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <cdall@linaro.org>
---
arch/arm/include/asm/kvm_asm.h | 2 --
arch/arm/include/asm/kvm_host.h | 2 +-
arch/arm/kvm/init.S | 2 --
3 files changed, 1 insertion(+), 5 deletions(-)
diff --git a/arch/arm/include/asm/kvm_asm.h b/arch/arm/include/asm/kvm_asm.h
index dd16044..eae11b3 100644
--- a/arch/arm/include/asm/kvm_asm.h
+++ b/arch/arm/include/asm/kvm_asm.h
@@ -72,8 +72,6 @@ extern int __kvm_vcpu_run(struct kvm_vcpu *vcpu);
extern void __init_stage2_translation(void);
-extern void __kvm_hyp_reset(unsigned long);
-
extern u64 __vgic_v3_get_ich_vtr_el2(void);
extern u64 __vgic_v3_read_vmcr(void);
extern void __vgic_v3_write_vmcr(u32 vmcr);
diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
index 31ee468..adea307 100644
--- a/arch/arm/include/asm/kvm_host.h
+++ b/arch/arm/include/asm/kvm_host.h
@@ -273,7 +273,7 @@ static inline void __cpu_init_stage2(void)
static inline void __cpu_reset_hyp_mode(unsigned long vector_ptr,
phys_addr_t phys_idmap_start)
{
- kvm_call_hyp((void *)virt_to_idmap(__kvm_hyp_reset), vector_ptr);
+ __hyp_reset_vectors();
}
static inline int kvm_arch_dev_ioctl_check_extension(struct kvm *kvm, long ext)
diff --git a/arch/arm/kvm/init.S b/arch/arm/kvm/init.S
index d6b2f49..fb33609 100644
--- a/arch/arm/kvm/init.S
+++ b/arch/arm/kvm/init.S
@@ -129,7 +129,6 @@ ENTRY(__kvm_handle_stub_hvc)
1: cmp r0, #HVC_RESET_VECTORS
bne 1f
-ENTRY(__kvm_hyp_reset)
/* We're now in idmap, disable MMU */
mrc p15, 4, r1, c1, c0, 0 @ HSCTLR
ldr r0, =(HSCTLR_M | HSCTLR_A | HSCTLR_C | HSCTLR_I)
@@ -151,7 +150,6 @@ ENTRY(__kvm_hyp_reset)
exit:
eret
ENDPROC(__kvm_handle_stub_hvc)
-ENDPROC(__kvm_hyp_reset)
.ltorg
--
2.9.0
^ permalink raw reply related
* [PULL 57/79] ARM: KVM: Allow the main HYP code to use the init hyp stub implementation
From: Christoffer Dall @ 2017-04-23 17:09 UTC (permalink / raw)
To: linux-arm-kernel
In-Reply-To: <20170423170929.27334-1-cdall@linaro.org>
From: Marc Zyngier <marc.zyngier@arm.com>
We now have a full hyp-stub implementation in the KVM init code,
but the main KVM code only supports HVC_GET_VECTORS, which is not
enough.
Instead of reinventing the wheel, let's reuse the init implementation
by branching to the idmap page when called with a hyp-stub hypercall.
Tested-by: Keerthy <j-keerthy@ti.com>
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <cdall@linaro.org>
---
arch/arm/kvm/hyp/hyp-entry.S | 29 ++++++++++++++++++++++++-----
1 file changed, 24 insertions(+), 5 deletions(-)
diff --git a/arch/arm/kvm/hyp/hyp-entry.S b/arch/arm/kvm/hyp/hyp-entry.S
index 1f8db7d..a35baa8 100644
--- a/arch/arm/kvm/hyp/hyp-entry.S
+++ b/arch/arm/kvm/hyp/hyp-entry.S
@@ -126,11 +126,30 @@ hyp_hvc:
*/
pop {r0, r1, r2}
- /* Check for __hyp_get_vectors */
- cmp r0, #HVC_GET_VECTORS
- mrceq p15, 4, r0, c12, c0, 0 @ get HVBAR
- beq 1f
+ /*
+ * Check if we have a kernel function, which is guaranteed to be
+ * bigger than the maximum hyp stub hypercall
+ */
+ cmp r0, #HVC_STUB_HCALL_NR
+ bhs 1f
+ /*
+ * Not a kernel function, treat it as a stub hypercall.
+ * Compute the physical address for __kvm_handle_stub_hvc
+ * (as the code lives in the idmaped page) and branch there.
+ * We hijack ip (r12) as a tmp register.
+ */
+ push {r1}
+ ldr r1, =kimage_voffset
+ ldr r1, [r1]
+ ldr ip, =__kvm_handle_stub_hvc
+ sub ip, ip, r1
+THUMB( add ip, ip, #1)
+ pop {r1}
+
+ bx ip
+
+1:
push {lr}
mov lr, r0
@@ -142,7 +161,7 @@ THUMB( orr lr, #1)
blx lr @ Call the HYP function
pop {lr}
-1: eret
+ eret
guest_trap:
load_vcpu r0 @ Load VCPU pointer to r0
--
2.9.0
^ permalink raw reply related
* [PULL 56/79] ARM: KVM: Implement HVC_GET_VECTORS in the init code
From: Christoffer Dall @ 2017-04-23 17:09 UTC (permalink / raw)
To: linux-arm-kernel
In-Reply-To: <20170423170929.27334-1-cdall@linaro.org>
From: Marc Zyngier <marc.zyngier@arm.com>
Now that we have an infrastructure to handle hypercalls in the KVM
init code, let's implement HVC_GET_VECTORS there.
Tested-by: Keerthy <j-keerthy@ti.com>
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <cdall@linaro.org>
---
arch/arm/kvm/init.S | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/arch/arm/kvm/init.S b/arch/arm/kvm/init.S
index 86a7008..d6b2f49 100644
--- a/arch/arm/kvm/init.S
+++ b/arch/arm/kvm/init.S
@@ -122,7 +122,12 @@ __do_hyp_init:
eret
ENTRY(__kvm_handle_stub_hvc)
- cmp r0, #HVC_RESET_VECTORS
+ cmp r0, #HVC_GET_VECTORS
+ bne 1f
+ mrc p15, 4, r0, c12, c0, 0 @ get HVBAR
+ b exit
+
+1: cmp r0, #HVC_RESET_VECTORS
bne 1f
ENTRY(__kvm_hyp_reset)
/* We're now in idmap, disable MMU */
--
2.9.0
^ permalink raw reply related
* [PULL 55/79] ARM: KVM: Implement HVC_RESET_VECTORS stub hypercall in the init code
From: Christoffer Dall @ 2017-04-23 17:09 UTC (permalink / raw)
To: linux-arm-kernel
In-Reply-To: <20170423170929.27334-1-cdall@linaro.org>
From: Marc Zyngier <marc.zyngier@arm.com>
In order to restore HYP mode to its original condition, KVM currently
implements __kvm_hyp_reset(). As we're moving towards a hyp-stub
defined API, it becomes necessary to implement HVC_RESET_VECTORS.
This patch adds the HVC_RESET_VECTORS hypercall to the KVM init
code, which so far lacked any form of hypercall support.
Tested-by: Keerthy <j-keerthy@ti.com>
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <cdall@linaro.org>
---
arch/arm/include/asm/virt.h | 1 +
arch/arm/kernel/hyp-stub.S | 2 +-
arch/arm/kvm/init.S | 33 +++++++++++++++++++++++++++------
3 files changed, 29 insertions(+), 7 deletions(-)
diff --git a/arch/arm/include/asm/virt.h b/arch/arm/include/asm/virt.h
index c5a2757..663adc0 100644
--- a/arch/arm/include/asm/virt.h
+++ b/arch/arm/include/asm/virt.h
@@ -54,6 +54,7 @@ static inline void sync_boot_mode(void)
void __hyp_set_vectors(unsigned long phys_vector_base);
unsigned long __hyp_get_vectors(void);
+void __hyp_reset_vectors(void);
#else
#define __boot_cpu_mode (SVC_MODE)
#define sync_boot_mode()
diff --git a/arch/arm/kernel/hyp-stub.S b/arch/arm/kernel/hyp-stub.S
index e637854..675c50f 100644
--- a/arch/arm/kernel/hyp-stub.S
+++ b/arch/arm/kernel/hyp-stub.S
@@ -280,7 +280,7 @@ ENDPROC(__hyp_reset_vectors)
#endif
.align 5
-__hyp_stub_vectors:
+ENTRY(__hyp_stub_vectors)
__hyp_stub_reset: W(b) .
__hyp_stub_und: W(b) .
__hyp_stub_svc: W(b) .
diff --git a/arch/arm/kvm/init.S b/arch/arm/kvm/init.S
index bf89c91..86a7008 100644
--- a/arch/arm/kvm/init.S
+++ b/arch/arm/kvm/init.S
@@ -23,6 +23,7 @@
#include <asm/kvm_asm.h>
#include <asm/kvm_arm.h>
#include <asm/kvm_mmu.h>
+#include <asm/virt.h>
/********************************************************************
* Hypervisor initialization
@@ -39,6 +40,10 @@
* - Setup the page tables
* - Enable the MMU
* - Profit! (or eret, if you only care about the code).
+ *
+ * Another possibility is to get a HYP stub hypercall.
+ * We discriminate between the two by checking if r0 contains a value
+ * that is less than HVC_STUB_HCALL_NR.
*/
.text
@@ -58,6 +63,10 @@ __kvm_hyp_init:
W(b) .
__do_hyp_init:
+ @ Check for a stub hypercall
+ cmp r0, #HVC_STUB_HCALL_NR
+ blo __kvm_handle_stub_hvc
+
@ Set stack pointer
mov sp, r0
@@ -112,19 +121,31 @@ __do_hyp_init:
eret
- @ r0 : stub vectors address
+ENTRY(__kvm_handle_stub_hvc)
+ cmp r0, #HVC_RESET_VECTORS
+ bne 1f
ENTRY(__kvm_hyp_reset)
/* We're now in idmap, disable MMU */
mrc p15, 4, r1, c1, c0, 0 @ HSCTLR
- ldr r2, =(HSCTLR_M | HSCTLR_A | HSCTLR_C | HSCTLR_I)
- bic r1, r1, r2
+ ldr r0, =(HSCTLR_M | HSCTLR_A | HSCTLR_C | HSCTLR_I)
+ bic r1, r1, r0
mcr p15, 4, r1, c1, c0, 0 @ HSCTLR
- /* Install stub vectors */
- mcr p15, 4, r0, c12, c0, 0 @ HVBAR
- isb
+ /*
+ * Install stub vectors, using ardb's VA->PA trick.
+ */
+0: adr r0, 0b @ PA(0)
+ movw r1, #:lower16:__hyp_stub_vectors - 0b @ VA(stub) - VA(0)
+ movt r1, #:upper16:__hyp_stub_vectors - 0b
+ add r1, r1, r0 @ PA(stub)
+ mcr p15, 4, r1, c12, c0, 0 @ HVBAR
+ b exit
+
+1: ldr r0, =HVC_STUB_ERR
+exit:
eret
+ENDPROC(__kvm_handle_stub_hvc)
ENDPROC(__kvm_hyp_reset)
.ltorg
--
2.9.0
^ permalink raw reply related
* [PULL 54/79] ARM: hyp-stub: Implement HVC_RESET_VECTORS stub hypercall
From: Christoffer Dall @ 2017-04-23 17:09 UTC (permalink / raw)
To: linux-arm-kernel
In-Reply-To: <20170423170929.27334-1-cdall@linaro.org>
From: Marc Zyngier <marc.zyngier@arm.com>
Let's define a new stub hypercall that resets the HYP configuration
to its default: hyp-stub vectors, and MMU disabled.
Of course, for the hyp-stub itself, this is a trivial no-op.
Hypervisors will have a bit more work to do.
Tested-by: Keerthy <j-keerthy@ti.com>
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <cdall@linaro.org>
---
arch/arm/include/asm/virt.h | 3 +++
arch/arm/kernel/hyp-stub.S | 11 ++++++++++-
2 files changed, 13 insertions(+), 1 deletion(-)
diff --git a/arch/arm/include/asm/virt.h b/arch/arm/include/asm/virt.h
index c16f70d..c5a2757 100644
--- a/arch/arm/include/asm/virt.h
+++ b/arch/arm/include/asm/virt.h
@@ -101,6 +101,9 @@ extern char __hyp_text_end[];
#define HVC_GET_VECTORS 0
#define HVC_SET_VECTORS 1
#define HVC_SOFT_RESTART 2
+#define HVC_RESET_VECTORS 3
+
+#define HVC_STUB_HCALL_NR 4
#endif /* __ASSEMBLY__ */
diff --git a/arch/arm/kernel/hyp-stub.S b/arch/arm/kernel/hyp-stub.S
index b20ca88..e637854 100644
--- a/arch/arm/kernel/hyp-stub.S
+++ b/arch/arm/kernel/hyp-stub.S
@@ -216,7 +216,10 @@ __hyp_stub_do_trap:
bne 1f
bx r1
-1: ldr r0, =HVC_STUB_ERR
+1: teq r0, #HVC_RESET_VECTORS
+ beq __hyp_stub_exit
+
+ ldr r0, =HVC_STUB_ERR
__hyp_stub_exit:
__ERET
@@ -264,6 +267,12 @@ ENTRY(__hyp_soft_restart)
ret lr
ENDPROC(__hyp_soft_restart)
+ENTRY(__hyp_reset_vectors)
+ mov r0, #HVC_RESET_VECTORS
+ __HVC(0)
+ ret lr
+ENDPROC(__hyp_reset_vectors)
+
#ifndef ZIMAGE
.align 2
.L__boot_cpu_mode_offset:
--
2.9.0
^ permalink raw reply related
* [PULL 53/79] ARM: hyp-stub: Define a return value for failed stub calls
From: Christoffer Dall @ 2017-04-23 17:09 UTC (permalink / raw)
To: linux-arm-kernel
In-Reply-To: <20170423170929.27334-1-cdall@linaro.org>
From: Marc Zyngier <marc.zyngier@arm.com>
Define a standard return value to be returned when a hyp stub
call fails.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <cdall@linaro.org>
---
arch/arm/include/asm/virt.h | 2 ++
arch/arm/kernel/hyp-stub.S | 2 +-
2 files changed, 3 insertions(+), 1 deletion(-)
diff --git a/arch/arm/include/asm/virt.h b/arch/arm/include/asm/virt.h
index 4ea16fc..c16f70d 100644
--- a/arch/arm/include/asm/virt.h
+++ b/arch/arm/include/asm/virt.h
@@ -104,4 +104,6 @@ extern char __hyp_text_end[];
#endif /* __ASSEMBLY__ */
+#define HVC_STUB_ERR 0xbadca11
+
#endif /* ! VIRT_H */
diff --git a/arch/arm/kernel/hyp-stub.S b/arch/arm/kernel/hyp-stub.S
index 15eaa14..b20ca88 100644
--- a/arch/arm/kernel/hyp-stub.S
+++ b/arch/arm/kernel/hyp-stub.S
@@ -216,7 +216,7 @@ __hyp_stub_do_trap:
bne 1f
bx r1
-1: mov r0, #-1
+1: ldr r0, =HVC_STUB_ERR
__hyp_stub_exit:
__ERET
--
2.9.0
^ permalink raw reply related
* [PULL 52/79] ARM: Expose the VA/IDMAP offset
From: Christoffer Dall @ 2017-04-23 17:09 UTC (permalink / raw)
To: linux-arm-kernel
In-Reply-To: <20170423170929.27334-1-cdall@linaro.org>
From: Marc Zyngier <marc.zyngier@arm.com>
The KVM code needs to be able to compute the address of
symbols in its idmap page (the equivalent of a virt_to_idmap()
call). Unfortunately, virt_to_idmap is slightly complicated,
depending on the use of arch_phys_to_idmap_offset or not, and
none of that is readily available at HYP.
Instead, expose a single kimage_voffset variable which contains the
offset between a kernel VA and its idmap address, enabling the
VA->IDMAP conversion. This allows the KVM code to behave similarily
to its arm64 counterpart.
Tested-by: Keerthy <j-keerthy@ti.com>
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <cdall@linaro.org>
---
arch/arm/mm/mmu.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index 4e016d7..e98a2b5 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -87,6 +87,8 @@ struct cachepolicy {
#define s2_policy(policy) 0
#endif
+unsigned long kimage_voffset __ro_after_init;
+
static struct cachepolicy cache_policies[] __initdata = {
{
.policy = "uncached",
@@ -1635,4 +1637,7 @@ void __init paging_init(const struct machine_desc *mdesc)
empty_zero_page = virt_to_page(zero_page);
__flush_dcache_page(NULL, empty_zero_page);
+
+ /* Compute the virt/idmap offset, mostly for the sake of KVM */
+ kimage_voffset = (unsigned long)&kimage_voffset - virt_to_idmap(&kimage_voffset);
}
--
2.9.0
^ permalink raw reply related
* [PULL 51/79] ARM: hyp-stub: Use r1 for the soft-restart address
From: Christoffer Dall @ 2017-04-23 17:09 UTC (permalink / raw)
To: linux-arm-kernel
In-Reply-To: <20170423170929.27334-1-cdall@linaro.org>
From: Marc Zyngier <marc.zyngier@arm.com>
It is not really obvious why the restart address should be in r3
when communicated to the hyp-stub. r1 should be perfectly adequate,
and consistent with the rest of the code.
Tested-by: Keerthy <j-keerthy@ti.com>
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <cdall@linaro.org>
---
arch/arm/kernel/hyp-stub.S | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/arch/arm/kernel/hyp-stub.S b/arch/arm/kernel/hyp-stub.S
index 8301db9..15eaa14 100644
--- a/arch/arm/kernel/hyp-stub.S
+++ b/arch/arm/kernel/hyp-stub.S
@@ -214,7 +214,7 @@ __hyp_stub_do_trap:
1: teq r0, #HVC_SOFT_RESTART
bne 1f
- bx r3
+ bx r1
1: mov r0, #-1
@@ -258,10 +258,9 @@ ENTRY(__hyp_set_vectors)
ENDPROC(__hyp_set_vectors)
ENTRY(__hyp_soft_restart)
- mov r3, r0
+ mov r1, r0
mov r0, #HVC_SOFT_RESTART
__HVC(0)
- mov r0, r3
ret lr
ENDPROC(__hyp_soft_restart)
--
2.9.0
^ permalink raw reply related
* [PULL 50/79] ARM: Update cpu_v7_reset documentation
From: Christoffer Dall @ 2017-04-23 17:09 UTC (permalink / raw)
To: linux-arm-kernel
In-Reply-To: <20170423170929.27334-1-cdall@linaro.org>
From: Marc Zyngier <marc.zyngier@arm.com>
cpu_v7_reset() now takes a second parameter indicating whether
we should reboot in HYP or not. Update the documentation to
reflect this.
Tested-by: Keerthy <j-keerthy@ti.com>
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <cdall@linaro.org>
---
arch/arm/mm/proc-v7.S | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S
index 1846ca4..01d64c0 100644
--- a/arch/arm/mm/proc-v7.S
+++ b/arch/arm/mm/proc-v7.S
@@ -39,13 +39,14 @@ ENTRY(cpu_v7_proc_fin)
ENDPROC(cpu_v7_proc_fin)
/*
- * cpu_v7_reset(loc)
+ * cpu_v7_reset(loc, hyp)
*
* Perform a soft reset of the system. Put the CPU into the
* same state as it would be if it had been reset, and branch
* to what would be the reset vector.
*
* - loc - location to jump to for soft reset
+ * - hyp - indicate if restart occurs in HYP mode
*
* This code must be executed using a flat identity mapping with
* caches disabled.
--
2.9.0
^ permalink raw reply related
* [PULL 49/79] ARM: KVM: Convert KVM to use HVC_GET_VECTORS
From: Christoffer Dall @ 2017-04-23 17:08 UTC (permalink / raw)
To: linux-arm-kernel
In-Reply-To: <20170423170929.27334-1-cdall@linaro.org>
From: Marc Zyngier <marc.zyngier@arm.com>
The conversion of the HYP stub ABI to something similar to arm64
left the KVM code broken, as it doesn't know about the new
stub numbering. Let's move the various #defines to virt.h, and
let KVM use HVC_GET_VECTORS.
Tested-by: Keerthy <j-keerthy@ti.com>
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <cdall@linaro.org>
---
arch/arm/include/asm/virt.h | 8 ++++++++
arch/arm/kernel/hyp-stub.S | 4 ----
arch/arm/kvm/hyp/hyp-entry.S | 2 +-
3 files changed, 9 insertions(+), 5 deletions(-)
diff --git a/arch/arm/include/asm/virt.h b/arch/arm/include/asm/virt.h
index 6dae195..4ea16fc 100644
--- a/arch/arm/include/asm/virt.h
+++ b/arch/arm/include/asm/virt.h
@@ -94,6 +94,14 @@ extern char __hyp_text_start[];
extern char __hyp_text_end[];
#endif
+#else
+
+/* Only assembly code should need those */
+
+#define HVC_GET_VECTORS 0
+#define HVC_SET_VECTORS 1
+#define HVC_SOFT_RESTART 2
+
#endif /* __ASSEMBLY__ */
#endif /* ! VIRT_H */
diff --git a/arch/arm/kernel/hyp-stub.S b/arch/arm/kernel/hyp-stub.S
index 8291523..8301db9 100644
--- a/arch/arm/kernel/hyp-stub.S
+++ b/arch/arm/kernel/hyp-stub.S
@@ -22,10 +22,6 @@
#include <asm/assembler.h>
#include <asm/virt.h>
-#define HVC_GET_VECTORS 0
-#define HVC_SET_VECTORS 1
-#define HVC_SOFT_RESTART 2
-
#ifndef ZIMAGE
/*
* For the kernel proper, we need to find out the CPU boot mode long after
diff --git a/arch/arm/kvm/hyp/hyp-entry.S b/arch/arm/kvm/hyp/hyp-entry.S
index 96beb53..1f8db7d 100644
--- a/arch/arm/kvm/hyp/hyp-entry.S
+++ b/arch/arm/kvm/hyp/hyp-entry.S
@@ -127,7 +127,7 @@ hyp_hvc:
pop {r0, r1, r2}
/* Check for __hyp_get_vectors */
- cmp r0, #-1
+ cmp r0, #HVC_GET_VECTORS
mrceq p15, 4, r0, c12, c0, 0 @ get HVBAR
beq 1f
--
2.9.0
^ permalink raw reply related
* [PULL 48/79] ARM: soft-reboot into same mode that we entered the kernel
From: Christoffer Dall @ 2017-04-23 17:08 UTC (permalink / raw)
To: linux-arm-kernel
In-Reply-To: <20170423170929.27334-1-cdall@linaro.org>
From: Russell King <rmk+kernel@armlinux.org.uk>
When we soft-reboot (eg, kexec) from one kernel into the next, we need
to ensure that we enter the new kernel in the same processor mode as
when we were entered, so that (eg) the new kernel can install its own
hypervisor - the old kernel's hypervisor will have been overwritten.
In order to do this, we need to pass a flag to cpu_reset() so it knows
what to do, and we need to modify the kernel's own hypervisor stub to
allow it to handle a soft-reboot.
As we are always guaranteed to install our own hypervisor if we're
entered in HYP32 mode, and KVM will have moved itself out of the way
on kexec/normal reboot, we can assume that our hypervisor is in place
when we want to kexec, so changing our hypervisor API should not be a
problem.
Tested-by: Keerthy <j-keerthy@ti.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <cdall@linaro.org>
---
arch/arm/include/asm/proc-fns.h | 4 ++--
arch/arm/kernel/hyp-stub.S | 13 +++++++++++++
arch/arm/kernel/reboot.c | 7 +++++--
arch/arm/mm/proc-v7.S | 12 ++++++++----
4 files changed, 28 insertions(+), 8 deletions(-)
diff --git a/arch/arm/include/asm/proc-fns.h b/arch/arm/include/asm/proc-fns.h
index 8877ad5..f2e1af4 100644
--- a/arch/arm/include/asm/proc-fns.h
+++ b/arch/arm/include/asm/proc-fns.h
@@ -43,7 +43,7 @@ extern struct processor {
/*
* Special stuff for a reset
*/
- void (*reset)(unsigned long addr) __attribute__((noreturn));
+ void (*reset)(unsigned long addr, bool hvc) __attribute__((noreturn));
/*
* Idle the processor
*/
@@ -88,7 +88,7 @@ extern void cpu_set_pte_ext(pte_t *ptep, pte_t pte);
#else
extern void cpu_set_pte_ext(pte_t *ptep, pte_t pte, unsigned int ext);
#endif
-extern void cpu_reset(unsigned long addr) __attribute__((noreturn));
+extern void cpu_reset(unsigned long addr, bool hvc) __attribute__((noreturn));
/* These three are private to arch/arm/kernel/suspend.c */
extern void cpu_do_suspend(void *);
diff --git a/arch/arm/kernel/hyp-stub.S b/arch/arm/kernel/hyp-stub.S
index f3e9ba5..8291523 100644
--- a/arch/arm/kernel/hyp-stub.S
+++ b/arch/arm/kernel/hyp-stub.S
@@ -24,6 +24,7 @@
#define HVC_GET_VECTORS 0
#define HVC_SET_VECTORS 1
+#define HVC_SOFT_RESTART 2
#ifndef ZIMAGE
/*
@@ -215,6 +216,10 @@ __hyp_stub_do_trap:
mcr p15, 4, r1, c12, c0, 0 @ set HVBAR
b __hyp_stub_exit
+1: teq r0, #HVC_SOFT_RESTART
+ bne 1f
+ bx r3
+
1: mov r0, #-1
__hyp_stub_exit:
@@ -256,6 +261,14 @@ ENTRY(__hyp_set_vectors)
ret lr
ENDPROC(__hyp_set_vectors)
+ENTRY(__hyp_soft_restart)
+ mov r3, r0
+ mov r0, #HVC_SOFT_RESTART
+ __HVC(0)
+ mov r0, r3
+ ret lr
+ENDPROC(__hyp_soft_restart)
+
#ifndef ZIMAGE
.align 2
.L__boot_cpu_mode_offset:
diff --git a/arch/arm/kernel/reboot.c b/arch/arm/kernel/reboot.c
index 3fa867a..3b2aa9a 100644
--- a/arch/arm/kernel/reboot.c
+++ b/arch/arm/kernel/reboot.c
@@ -12,10 +12,11 @@
#include <asm/cacheflush.h>
#include <asm/idmap.h>
+#include <asm/virt.h>
#include "reboot.h"
-typedef void (*phys_reset_t)(unsigned long);
+typedef void (*phys_reset_t)(unsigned long, bool);
/*
* Function pointers to optional machine specific functions
@@ -51,7 +52,9 @@ static void __soft_restart(void *addr)
/* Switch to the identity mapping. */
phys_reset = (phys_reset_t)virt_to_idmap(cpu_reset);
- phys_reset((unsigned long)addr);
+
+ /* original stub should be restored by kvm */
+ phys_reset((unsigned long)addr, is_hyp_mode_available());
/* Should never get here. */
BUG();
diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S
index d00d52c..1846ca4 100644
--- a/arch/arm/mm/proc-v7.S
+++ b/arch/arm/mm/proc-v7.S
@@ -53,11 +53,15 @@ ENDPROC(cpu_v7_proc_fin)
.align 5
.pushsection .idmap.text, "ax"
ENTRY(cpu_v7_reset)
- mrc p15, 0, r1, c1, c0, 0 @ ctrl register
- bic r1, r1, #0x1 @ ...............m
- THUMB( bic r1, r1, #1 << 30 ) @ SCTLR.TE (Thumb exceptions)
- mcr p15, 0, r1, c1, c0, 0 @ disable MMU
+ mrc p15, 0, r2, c1, c0, 0 @ ctrl register
+ bic r2, r2, #0x1 @ ...............m
+ THUMB( bic r2, r2, #1 << 30 ) @ SCTLR.TE (Thumb exceptions)
+ mcr p15, 0, r2, c1, c0, 0 @ disable MMU
isb
+#ifdef CONFIG_ARM_VIRT_EXT
+ teq r1, #0
+ bne __hyp_soft_restart
+#endif
bx r0
ENDPROC(cpu_v7_reset)
.popsection
--
2.9.0
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