- 10 Nov, 2017 15 commits
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Marc Zyngier authored
The doorbell interrupt is only useful if the vcpu is blocked on WFI. In all other cases, recieving a doorbell interrupt is just a waste of cycles. So let's only enable the doorbell if a vcpu is getting blocked, and disable it when it is unblocked. This is very similar to what we're doing for the background timer. Reviewed-by:
Christoffer Dall <cdall@linaro.org> Reviewed-by:
Eric Auger <eric.auger@redhat.com> Signed-off-by:
Marc Zyngier <marc.zyngier@arm.com> Signed-off-by:
Christoffer Dall <christoffer.dall@linaro.org>
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Marc Zyngier authored
When a vPE is not running, a VLPI being made pending results in a doorbell interrupt being delivered. Let's handle this interrupt and update the pending_last flag that indicates that VLPIs are pending. The corresponding vcpu is also kicked into action. Special care is taken to prevent the doorbell from being enabled at request time (this is controlled separately), and to make the disabling on the interrupt non-lazy. Reviewed-by:
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Marc Zyngier authored
When a vPE exits, the pending_last flag is set when there are pending VLPIs stored in the pending table. Similarily, this flag will be set when a doorbell interrupt fires, as it indicates the same condition. Let's update kvm_vgic_vcpu_pending_irq() to account for that flag as well, making a vcpu runnable when set. Acked-by:
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Marc Zyngier authored
There is no need to perform an INV for each interrupt when updating multiple interrupts. Instead, we can rely on the final VINVALL that gets sent to the ITS to do the work for all of them. Acked-by:
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Marc Zyngier authored
Upon updating a property, we propagate it all the way to the physical ITS, and ask for an INV command to be executed there. Acked-by:
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Marc Zyngier authored
The current implementation of MOVALL doesn't allow us to call into the core ITS code as we hold a number of spinlocks. Let's try a method used in other parts of the code, were we copy the intids of the candicate interrupts, and then do whatever we need to do with them outside of the critical section. This allows us to move the interrupts one by one, at the expense of a bit of CPU time. Who cares? MOVALL is such a stupid command anyway... Reviewed-by:
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Marc Zyngier authored
Handling CLEAR is pretty easy. Just ask the ITS driver to clear the corresponding pending bit (which will turn into a CLEAR command on the physical side). Acked-by:
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Marc Zyngier authored
When the guest issues an affinity change, we need to tell the physical ITS that we're now targetting a new vcpu. This is done by extracting the current mapping, updating the target, and reapplying the mapping. Reviewed-by:
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Marc Zyngier authored
When freeing an LPI (on a DISCARD command, for example), we need to unmap the VLPI down to the physical ITS level. Acked-by:
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Marc Zyngier authored
If the guest issues an INT command targetting a VLPI, let's call into the irq_set_irqchip_state() helper to make it pending on the physical side. This works just as well if userspace decides to inject an interrupt using the normal userspace API... Acked-by:
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Marc Zyngier authored
Let's use the irq bypass mechanism also used for x86 posted interrupts to intercept the virtual PCIe endpoint configuration and establish our LPI->VLPI mapping. Reviewed-by:
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Marc Zyngier authored
In order to control the GICv4 view of virtual CPUs, we rely on an irqdomain allocated for that purpose. Let's add a couple of helpers to that effect. At the same time, the vgic data structures gain new fields to track all this... erm... wonderful stuff. The way we hook into the vgic init is slightly convoluted. We need the vgic to be initialized (in order to guarantee that the number of vcpus is now fixed), and we must have a vITS (otherwise this is all very pointless). So we end-up calling the init from both vgic_init and vgic_its_create. Reviewed-by:
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Marc Zyngier authored
Add a new has_gicv4 field in the global VGIC state that indicates whether the HW is GICv4 capable, as a per-VM predicate indicating if there is a possibility for a VM to support direct injection (the above being true and the VM having an ITS). Reviewed-by:
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Marc Zyngier authored
In order to help integrating the vITS code with GICv4, let's add a new helper that deals with updating the affinity of an LPI, which will later be augmented with super duper extra GICv4 goodness. Reviewed-by:
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Marc Zyngier authored
The whole MSI injection process is fairly monolithic. An MSI write gets turned into an injected LPI in one swift go. But this is actually a more fine-grained process: - First, a virtual ITS gets selected using the doorbell address - Then the DevID/EventID pair gets translated into an LPI - Finally the LPI is injected Since the GICv4 code needs the first two steps in order to match an IRQ routing entry to an LPI, let's expose them as helpers, and refactor the existing code to use them Reviewed-by:
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- 06 Nov, 2017 25 commits
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Marc Zyngier authored
The way we call kvm_vgic_destroy is a bit bizarre. We call it *after* having freed the vcpus, which sort of defeats the point of cleaning up things before that point. Let's move kvm_vgic_destroy towards the beginning of kvm_arch_destroy_vm, which seems more sensible. Acked-by:
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Marc Zyngier authored
The GICv4 support introduces a hard dependency between the KVM core and the ITS infrastructure. arm64 already selects it at the architecture level, but 32bit doesn't. In order to avoid littering the kernel with #ifdefs, let's just select the whole of the GICv3 suport code. You know you want it. Acked-by:
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Eric Auger authored
We want to reuse the core of the map/unmap functions for IRQ forwarding. Let's move the computation of the hwirq in kvm_vgic_map_phys_irq and pass the linux IRQ as parameter. the host_irq is added to struct vgic_irq. We introduce kvm_vgic_map/unmap_irq which take a struct vgic_irq handle as a parameter. Acked-by:
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Eric Auger authored
This patch selects IRQ_BYPASS_MANAGER and HAVE_KVM_IRQ_BYPASS configs for ARM/ARM64. kvm_arch_has_irq_bypass() now is implemented and returns true. As a consequence the irq bypass consumer will be registered for ARM/ARM64 with the forwarding callbacks: - stop/start: halt/resume guest execution - add/del_producer: set/unset forwarding at vgic/irqchip level We don't have any actual support yet, so nothing gets actually forwarded. Acked-by:
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Dongjiu Geng authored
kvm_vcpu_dabt_isextabt() tries to match a full fault syndrome, but calls kvm_vcpu_trap_get_fault_type() that only returns the fault class, thus reducing the scope of the check. This doesn't cause any observable bug yet as we end-up matching a closely related syndrome for which we return the same value. Using kvm_vcpu_trap_get_fault() instead fixes it for good. Signed-off-by:
Dongjiu Geng <gengdongjiu@huawei.com> Acked-by:
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Marc Zyngier authored
Both arm and arm64 implementations are capable of injecting faults, and yet have completely divergent implementations, leading to different bugs and reduced maintainability. Let's elect the arm64 version as the canonical one and move it into aarch32.c, which is common to both architectures. Reviewed-by:
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Eric Auger authored
On reset we clear the valid bits of GITS_CBASER and GITS_BASER<n>. We also clear command queue registers and free the cache (device, collection, and lpi lists). As we need to take the same locks as save/restore functions, we create a vgic_its_ctrl() wrapper that handles KVM_DEV_ARM_VGIC_GRP_CTRL group functions. Reviewed-by:
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Eric Auger authored
At the moment, the in-kernel emulated ITS is not properly reset. On guest restart/reset some registers keep their old values and internal structures like device, ITE, and collection lists are not freed. This may lead to various bugs. Among them, we can have incorrect state backup or failure when saving the ITS state at early guest boot stage. This patch documents a new attribute, KVM_DEV_ARM_ITS_CTRL_RESET in the KVM_DEV_ARM_VGIC_GRP_CTRL group. Upon this action, we can reset registers and especially those pointing to tables previously allocated by the guest and free the internal data structures storing the list of devices, collections and lpis. The usual approach for device reset of having userspace write the reset values of the registers to the kernel via the register read/write APIs doesn't work for the ITS because it has some internal state (caches) which is not exposed as registers, and there is no register interface for "drop cached data without writing it back to RAM". So we need a KVM API which mimics the hardware's reset line, to provide the equivalent behaviour to a "pull the power cord out of the back of the machine" reset. Reviewed-by:
wanghaibin <wanghaibin.wang@huawei.com> Signed-off-by:
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Eric Auger authored
When the GITS_BASER<n>.Valid gets cleared, the data structures in guest RAM are not valid anymore. The device, collection and LPI lists stored in the in-kernel ITS represent the same information in some form of cache. So let's void the cache. Reviewed-by:
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wanghaibin authored
We create two new functions that free the device and collection lists. They are currently called by vgic_its_destroy() and other callers will be added in subsequent patches. We also remove the check on its->device_list.next. Lists are initialized in vgic_create_its() and the device is added to the device list only if this latter succeeds. vgic_its_destroy is the device destroy ops. This latter is called by kvm_destroy_devices() which loops on all created devices. So at this point the list is initialized. Acked-by:
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Eric Auger authored
Let's remove kvm_its_unmap_device and use kvm_its_free_device as both functions are identical. Signed-off-by:
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Christoffer Dall authored
After being lazy with saving/restoring the timer state, we defer that work to vcpu_load and vcpu_put, which ensure that the timer state is loaded on the hardware timers whenever the VCPU runs. Unfortunately, we are failing to do that the first time vcpu_load() runs, because the timer has not yet been enabled at that time. As long as the initialized timer state matches what happens to be in the hardware (a disabled timer, because we never leave the timer screaming), this does not show up as a problem, but is nevertheless incorrect. The solution is simple; disable preemption while setting the timer to be enabled, and call the timer load function when first enabling the timer. Acked-by:
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Christoffer Dall authored
kvm_timer_should_fire() can be called in two different situations from the kvm_vcpu_block(). The first case is before calling kvm_timer_schedule(), used for wait polling, and in this case the VCPU thread is running and the timer state is loaded onto the hardware so all we have to do is check if the virtual interrupt lines are asserted, becasue the timer interrupt handler functions will raise those lines as appropriate. The second case is inside the wait loop of kvm_vcpu_block(), where we have already called kvm_timer_schedule() and therefore the hardware will be disabled and the software view of the timer state is up to date (timer->loaded is false), and so we can simply check if the timer should fire by looking at the software state. Signed-off-by:
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Christoffer Dall authored
Now when both the vtimer and the ptimer when using both the in-kernel vgic emulation and a userspace IRQ chip are driven by the timer signals and at the vcpu load/put boundaries, instead of recomputing the timer state at every entry/exit to/from the guest, we can get entirely rid of the flush hwstate function. Signed-off-by:
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Christoffer Dall authored
There is no need to schedule and cancel a hrtimer when entering and exiting the guest, because we know when the physical timer is going to fire when the guest programs it, and we can simply program the hrtimer at that point. Now when the register modifications from the guest go through the kvm_arm_timer_set/get_reg functions, which always call kvm_timer_update_state(), we can simply consider the timer state in this function and schedule and cancel the timers as needed. This avoids looking at the physical timer emulation state when entering and exiting the VCPU, allowing for faster servicing of the VM when needed. Signed-off-by:
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Christoffer Dall authored
We are about to call phys_timer_emulate() from kvm_timer_update_state() and modify phys_timer_emulate() at the same time. Moving the function and modifying it in a single patch makes the diff hard to read, so do this separately first. No functional change. Signed-off-by:
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Christoffer Dall authored
When trapping on a guest access to one of the timer registers, we were messing with the internals of the timer state from the sysregs handling code, and that logic was about to receive more added complexity when optimizing the timer handling code. Therefore, since we already have timer register access functions (to access registers from userspace), reuse those for the timer register traps from a VM and let the timer code maintain its own consistency. Signed-off-by:
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Christoffer Dall authored
Add suport for the physical timer registers in kvm_arm_timer_set_reg and kvm_arm_timer_get_reg so that these functions can be reused to interact with the rest of the system. Note that this paves part of the way for the physical timer state save/restore, but we still need to add those registers to KVM_GET_REG_LIST before we support migrating the physical timer state. Acked-by:
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Christoffer Dall authored
We don't need to save and restore the hardware timer state and examine if it generates interrupts on on every entry/exit to the guest. The timer hardware is perfectly capable of telling us when it has expired by signaling interrupts. When taking a vtimer interrupt in the host, we don't want to mess with the timer configuration, we just want to forward the physical interrupt to the guest as a virtual interrupt. We can use the split priority drop and deactivate feature of the GIC to do this, which leaves an EOI'ed interrupt active on the physical distributor, making sure we don't keep taking timer interrupts which would prevent the guest from running. We can then forward the physical interrupt to the VM using the HW bit in the LR of the GIC, like we do already, which lets the guest directly deactivate both the physical and virtual timer simultaneously, allowing the timer hardware to exit the VM and generate a new physical interrupt when the timer output is again asserted later on. We do need to capture this state when migrating VCPUs between physical CPUs, however, which we use the vcpu put/load functions for, which are called through preempt notifiers whenever the thread is scheduled away from the CPU or called directly if we return from the ioctl to userspace. One caveat is that we have to save and restore the timer state in both kvm_timer_vcpu_[put/load] and kvm_timer_[schedule/unschedule], because we can have the following flows: 1. kvm_vcpu_block 2. kvm_timer_schedule 3. schedule 4. kvm_timer_vcpu_put (preempt notifier) 5. schedule (vcpu thread gets scheduled back) 6. kvm_timer_vcpu_load (preempt notifier) 7. kvm_timer_unschedule And a version where we don't actually call schedule: 1. kvm_vcpu_block 2. kvm_timer_schedule 7. kvm_timer_unschedule Since kvm_timer_[schedule/unschedule] may not be followed by put/load, but put/load also may be called independently, we call the timer save/restore functions from both paths. Since they rely on the loaded flag to never save/restore when unnecessary, this doesn't cause any harm, and we ensure that all invokations of either set of functions work as intended. An added benefit beyond not having to read and write the timer sysregs on every entry and exit is that we no longer have to actively write the active state to the physical distributor, because we configured the irq for the vtimer to only get a priority drop when handling the interrupt in the GIC driver (we called irq_set_vcpu_affinity()), and the interrupt stays active after firing on the host. Reviewed-by:
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Christoffer Dall authored
As we are about to take physical interrupts for the virtual timer on the host but want to leave those active while running the VM (and let the VM deactivate them), we need to set the vtimer PPI affinity accordingly. Signed-off-by:
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Christoffer Dall authored
As we are about to be lazy with saving and restoring the timer registers, we prepare by moving all possible timer configuration logic out of the hyp code. All virtual timer registers can be programmed from EL1 and since the arch timer is always a level triggered interrupt we can safely do this with interrupts disabled in the host kernel on the way to the guest without taking vtimer interrupts in the host kernel (yet). The downside is that the cntvoff register can only be programmed from hyp mode, so we jump into hyp mode and back to program it. This is also safe, because the host kernel doesn't use the virtual timer in the KVM code. It may add a little performance performance penalty, but only until following commits where we move this operation to vcpu load/put. Signed-off-by:
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Christoffer Dall authored
We were using the same hrtimer for emulating the physical timer and for making sure a blocking VCPU thread would be eventually woken up. That worked fine in the previous arch timer design, but as we are about to actually use the soft timer expire function for the physical timer emulation, change the logic to use a dedicated hrtimer. This has the added benefit of not having to cancel any work in the sync path, which in turn allows us to run the flush and sync with IRQs disabled. Note that the hrtimer used to program the host kernel's timer to generate an exit from the guest when the emulated physical timer fires never has to inject any work, and to share the soft_timer_cancel() function with the bg_timer, we change the function to only cancel any pending work if the pointer to the work struct is not null. Acked-by:
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Christoffer Dall authored
As we are about to play tricks with the timer to be more lazy in saving and restoring state, we need to move the timer sync and flush functions under a disabled irq section and since we have to flush the vgic state after the timer and PMU state, we do the whole flush/sync sequence with disabled irqs. The only downside is a slightly longer delay before being able to process hardware interrupts and run softirqs. Signed-off-by:
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Christoffer Dall authored
As we are about to introduce a separate hrtimer for the physical timer, call this timer bg_timer, because we refer to this timer as the background timer in the code and comments elsewhere. Signed-off-by:
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