- 11 Mar, 2014 7 commits
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Paolo Bonzini authored
When not running in guest-debug mode, the guest controls the debug registers and having to take an exit for each DR access is a waste of time. If the guest gets into a state where each context switch causes DR to be saved and restored, this can take away as much as 40% of the execution time from the guest. After this patch, VMX- and SVM-specific code can set a flag in switch_db_regs, telling vcpu_enter_guest that on the next exit the debug registers might be dirty and need to be reloaded (syncing will be taken care of by a new callback in kvm_x86_ops). This flag can be set on the first access to a debug registers, so that multiple accesses to the debug registers only cause one vmexit. Note that since the guest will be able to read debug registers and enable breakpoints in DR7, we need to ensure that they are synchronized on entry to the guest---including DR6 that was not synced before. Signed-off-by:Paolo Bonzini <pbonzini@redhat.com>
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Paolo Bonzini authored
The next patch will add another bit that we can test with the same "if". Signed-off-by: -
Paolo Bonzini authored
Currently, this works even if the bit is not in "min", because the bit is always set in MSR_IA32_VMX_ENTRY_CTLS. Mention it for the sake of documentation, and to avoid surprises if we later switch to MSR_IA32_VMX_TRUE_ENTRY_CTLS. Signed-off-by: -
Jan Kiszka authored
It's no longer possible to enter enable_irq_window in guest mode when L1 intercepts external interrupts and we are entering L2. This is now caught in vcpu_enter_guest. So we can remove the check from the VMX version of enable_irq_window, thus the need to return an error code from both enable_irq_window and enable_nmi_window. Signed-off-by:
Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by:
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Jan Kiszka authored
According to SDM 27.2.3, IDT vectoring information will not be valid on vmexits caused by external NMIs. So we have to avoid creating such scenarios by delaying EXIT_REASON_EXCEPTION_NMI injection as long as we have a pending interrupt because that one would be migrated to L1's IDT vectoring info on nested exit. Signed-off-by:
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Jan Kiszka authored
We cannot rely on the hardware-provided preemption timer support because we are holding L2 in HLT outside non-root mode. Furthermore, emulating the preemption will resolve tick rate errata on older Intel CPUs. The emulation is based on hrtimer which is started on L2 entry, stopped on L2 exit and evaluated via the new check_nested_events hook. As we no longer rely on hardware features, we can enable both the preemption timer support and value saving unconditionally. Signed-off-by:
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Jan Kiszka authored
Move the check for leaving L2 on pending and intercepted IRQs or NMIs from the *_allowed handler into a dedicated callback. Invoke this callback at the relevant points before KVM checks if IRQs/NMIs can be injected. The callback has the task to switch from L2 to L1 if needed and inject the proper vmexit events. The rework fixes L2 wakeups from HLT and provides the foundation for preemption timer emulation. Signed-off-by:
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- 06 Mar, 2014 2 commits
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Paolo Bonzini authored
Merge tag 'kvm-s390-20140306' of git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into kvm-next One fix for virtio-ccw, fixing a problem introduced with "virtio_ccw: fix vcdev pointer handling issues" and noticed just after it went into git.
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Heinz Graalfs authored
During set offline processing virtio_grab_drvdata() incorrectly calls dev_set_drvdata() to remove the virtio_ccw_device from the parent ccw_device's driver data. This is wrong and ends up in a hang during virtio_ccw_reset(), as the interrupt handler still has need of the virtio_ccw_device. A new field 'going_away' is introduced in struct virtio_ccw_device to control the usage of the ccw_device's driver data pointer in virtio_grab_drvdata(). Signed-off-by:
Heinz Graalfs <graalfs@linux.vnet.ibm.com> Reviewed-by:
Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by:
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- 04 Mar, 2014 12 commits
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Paolo Bonzini authored
Merge tag 'kvm-for-3.15-1' of git://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms into kvm-next
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Paolo Bonzini authored
Merge tag 'kvm-s390-20140304' of git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into kvm-next
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Andrew Jones authored
commit 0061d53d introduced a mechanism to execute a global clock update for a vm. We can apply this periodically in order to propagate host NTP corrections. Also, if all vcpus of a vm are pinned, then without an additional trigger, no guest NTP corrections can propagate either, as the current trigger is only vcpu cpu migration. Signed-off-by:
Andrew Jones <drjones@redhat.com> Signed-off-by:
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Andrew Jones authored
When we update a vcpu's local clock it may pick up an NTP correction. We can't wait an indeterminate amount of time for other vcpus to pick up that correction, so commit 0061d53d introduced a global clock update. However, we can't request a global clock update on every vcpu load either (which is what happens if the tsc is marked as unstable). The solution is to rate-limit the global clock updates. Marcelo calculated that we should delay the global clock updates no more than 0.1s as follows: Assume an NTP correction c is applied to one vcpu, but not the other, then in n seconds the delta of the vcpu system_timestamps will be c * n. If we assume a correction of 500ppm (worst-case), then the two vcpus will diverge 50us in 0.1s, which is a considerable amount. Signed-off-by:
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Cornelia Huck authored
Implement the new CCW_CMD_SET_IND_ADAPTER command and try to enable adapter interrupts for every device on the first startup. If the host does not support adapter interrupts, fall back to normal I/O interrupts. virtio-ccw adapter interrupts use the same isc as normal I/O subchannels and share a summary indicator for all devices sharing the same indicator area. Indicator bits for the individual virtqueues may be contained in the same indicator area for different devices. Signed-off-by:
Christian Borntraeger <borntraeger@de.ibm.com>
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Martin Schwidefsky authored
Add airq_iv_alloc and airq_iv_free to allocate and free consecutive ranges of irqs from the interrupt vector. Signed-off-by:
Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by:
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Heinz Graalfs authored
The interrupt handler virtio_ccw_int_handler() using the vcdev pointer is protected by the ccw_device lock. Resetting the pointer within the ccw_device structure should be done when holding this lock. Also resetting the vcdev pointer (under the ccw_device lock) prior to freeing the vcdev pointer memory removes a critical path. Signed-off-by:
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Jens Freimann authored
We can use kvm_get_vcpu() now and don't need the local_int array in the floating_int struct anymore. This also means we don't have to hold the float_int.lock in some places. Signed-off-by:
Jens Freimann <jfrei@linux.vnet.ibm.com> Signed-off-by:
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Thomas Huth authored
When SIGP SET_PREFIX is called with an illegal CPU id, it must return the condition code 3 ("not operational") instead of 1. Also fixed the order in which the checks are done - CC3 has a higher priority than CC1. And while we're at it, this patch also get rid of the floating interrupt lock here by using kvm_get_vcpu() to get the local_int struct of the destination CPU. Signed-off-by:Thomas Huth <thuth@linux.vnet.ibm.com> Reviewed-by:
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Jens Freimann authored
We don't need to loop over all cpus to get the number of vcpus. Let's use the available counter online_vcpus instead. Signed-off-by:
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Christian Borntraeger authored
For migration/reset we want to expose the guest breaking event address register to userspace. Lets use ONE_REG for that purpose. Signed-off-by:
Jason J. Herne <jjherne@linux.vnet.ibm.com>
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Christian Borntraeger authored
commit d208c79d (KVM: s390: Enable the LPP facility for guests) enabled the LPP instruction for guests. We should expose the program parameter as a pseudo register for migration/reset etc. Lets also reset this value on initial CPU reset. Signed-off-by:
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- 03 Mar, 2014 13 commits
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Paolo Bonzini authored
Commit e504c909 (kvm, vmx: Fix lazy FPU on nested guest, 2013-11-13) highlighted a real problem, but the fix was subtly wrong. nested_read_cr0 is the CR0 as read by L2, but here we want to look at the CR0 value reflecting L1's setup. In other words, L2 might think that TS=0 (so nested_read_cr0 has the bit clear); but if L1 is actually running it with TS=1, we should inject the fault into L1. The effective value of CR0 in L2 is contained in vmcs12->guest_cr0, use it. Fixes: e504c909Reported-by:
Kashyap Chamarty <kchamart@redhat.com> Reported-by:
Stefan Bader <stefan.bader@canonical.com> Tested-by:
Anthoine Bourgeois <bourgeois@bertin.fr> Cc: stable@vger.kernel.org Signed-off-by:
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Marc Zyngier authored
Compiling with THP enabled leads to the following warning: arch/arm/kvm/mmu.c: In function ‘unmap_range’: arch/arm/kvm/mmu.c:177:39: warning: ‘pte’ may be used uninitialized in this function [-Wmaybe-uninitialized] if (kvm_pmd_huge(*pmd) || page_empty(pte)) { ^ Code inspection reveals that these two cases are mutually exclusive, so GCC is a bit overzealous here. Silence it anyway by initializing pte to NULL and testing it later on. Signed-off-by:Marc Zyngier <marc.zyngier@arm.com> Acked-by:
Christoffer Dall <christoffer.dall@linaro.org>
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Marc Zyngier authored
In order to be able to detect the point where the guest enables its MMU and caches, trap all the VM related system registers. Once we see the guest enabling both the MMU and the caches, we can go back to a saner mode of operation, which is to leave these registers in complete control of the guest. Signed-off-by:
Catalin Marinas <catalin.marinas@arm.com> Reviewed-by:
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Marc Zyngier authored
HCR.TVM traps (among other things) accesses to AMAIR0 and AMAIR1. In order to minimise the amount of surprise a guest could generate by trying to access these registers with caches off, add them to the list of registers we switch/handle. Signed-off-by:
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Marc Zyngier authored
So far, KVM/ARM used a fixed HCR configuration per guest, except for the VI/VF/VA bits to control the interrupt in absence of VGIC. With the upcoming need to dynamically reconfigure trapping, it becomes necessary to allow the HCR to be changed on a per-vcpu basis. The fix here is to mimic what KVM/arm64 already does: a per vcpu HCR field, initialized at setup time. Signed-off-by:
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Marc Zyngier authored
Commit 240e99cb (ARM: KVM: Fix 64-bit coprocessor handling) added an ordering dependency for the 64bit registers. The order described is: CRn, CRm, Op1, Op2, 64bit-first. Unfortunately, the implementation is: CRn, 64bit-first, CRm... Move the 64bit test to be last in order to match the documentation. Signed-off-by:
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Marc Zyngier authored
Commit 240e99cb (ARM: KVM: Fix 64-bit coprocessor handling) changed the way we match the 64bit coprocessor access from user space, but didn't update the trap handler for the same set of registers. The effect is that a trapped 64bit access is never matched, leading to a fault being injected into the guest. This went unnoticed as we didn't really trap any 64bit register so far. Placing the CRm field of the access into the CRn field of the matching structure fixes the problem. Also update the debug feature to emit the expected string in case of failing match. Signed-off-by:
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Marc Zyngier authored
In order for a guest with caches disabled to observe data written contained in a given page, we need to make sure that page is committed to memory, and not just hanging in the cache (as guest accesses are completely bypassing the cache until it decides to enable it). For this purpose, hook into the coherent_cache_guest_page function and flush the region if the guest SCTLR register doesn't show the MMU and caches as being enabled. Signed-off-by:
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Marc Zyngier authored
When the guest runs with caches disabled (like in an early boot sequence, for example), all the writes are diectly going to RAM, bypassing the caches altogether. Once the MMU and caches are enabled, whatever sits in the cache becomes suddenly visible, which isn't what the guest expects. A way to avoid this potential disaster is to invalidate the cache when the MMU is being turned on. For this, we hook into the SCTLR_EL1 trapping code, and scan the stage-2 page tables, invalidating the pages/sections that have already been mapped in. Signed-off-by:
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Marc Zyngier authored
The use of p*d_addr_end with stage-2 translation is slightly dodgy, as the IPA is 40bits, while all the p*d_addr_end helpers are taking an unsigned long (arm64 is fine with that as unligned long is 64bit). The fix is to introduce 64bit clean versions of the same helpers, and use them in the stage-2 page table code. Signed-off-by:
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Marc Zyngier authored
In order to be able to detect the point where the guest enables its MMU and caches, trap all the VM related system registers. Once we see the guest enabling both the MMU and the caches, we can go back to a saner mode of operation, which is to leave these registers in complete control of the guest. Signed-off-by:
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Marc Zyngier authored
The current handling of AArch32 trapping is slightly less than perfect, as it is not possible (from a handler point of view) to distinguish it from an AArch64 access, nor to tell a 32bit from a 64bit access either. Fix this by introducing two additional flags: - is_aarch32: true if the access was made in AArch32 mode - is_32bit: true if is_aarch32 == true and a MCR/MRC instruction was used to perform the access (as opposed to MCRR/MRRC). This allows a handler to cover all the possible conditions in which a system register gets trapped. Signed-off-by:
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Marc Zyngier authored
In order for the guest with caches off to observe data written contained in a given page, we need to make sure that page is committed to memory, and not just hanging in the cache (as guest accesses are completely bypassing the cache until it decides to enable it). For this purpose, hook into the coherent_icache_guest_page function and flush the region if the guest SCTLR_EL1 register doesn't show the MMU and caches as being enabled. The function also get renamed to coherent_cache_guest_page. Signed-off-by:
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- 27 Feb, 2014 4 commits
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Paolo Bonzini authored
Commit e504c909 (kvm, vmx: Fix lazy FPU on nested guest, 2013-11-13) highlighted a real problem, but the fix was subtly wrong. nested_read_cr0 is the CR0 as read by L2, but here we want to look at the CR0 value reflecting L1's setup. In other words, L2 might think that TS=0 (so nested_read_cr0 has the bit clear); but if L1 is actually running it with TS=1, we should inject the fault into L1. The effective value of CR0 in L2 is contained in vmcs12->guest_cr0, use it. Fixes: e504c909Reported-by:
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Andrew Honig authored
The problem occurs when the guest performs a pusha with the stack address pointing to an mmio address (or an invalid guest physical address) to start with, but then extending into an ordinary guest physical address. When doing repeated emulated pushes emulator_read_write sets mmio_needed to 1 on the first one. On a later push when the stack points to regular memory, mmio_nr_fragments is set to 0, but mmio_is_needed is not set to 0. As a result, KVM exits to userspace, and then returns to complete_emulated_mmio. In complete_emulated_mmio vcpu->mmio_cur_fragment is incremented. The termination condition of vcpu->mmio_cur_fragment == vcpu->mmio_nr_fragments is never achieved. The code bounces back and fourth to userspace incrementing mmio_cur_fragment past it's buffer. If the guest does nothing else it eventually leads to a a crash on a memcpy from invalid memory address. However if a guest code can cause the vm to be destroyed in another vcpu with excellent timing, then kvm_clear_async_pf_completion_queue can be used by the guest to control the data that's pointed to by the call to cancel_work_item, which can be used to gain execution. Fixes: f78146b0Signed-off-by:
Andrew Honig <ahonig@google.com> Cc: stable@vger.kernel.org (3.5+) Signed-off-by:
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Marc Zyngier authored
Commit 1fcf7ce0 (arm: kvm: implement CPU PM notifier) added support for CPU power-management, using a cpu_notifier to re-init KVM on a CPU that entered CPU idle. The code assumed that a CPU entering idle would actually be powered off, loosing its state entierely, and would then need to be reinitialized. It turns out that this is not always the case, and some HW performs CPU PM without actually killing the core. In this case, we try to reinitialize KVM while it is still live. It ends up badly, as reported by Andre Przywara (using a Calxeda Midway): [ 3.663897] Kernel panic - not syncing: unexpected prefetch abort in Hyp mode at: 0x685760 [ 3.663897] unexpected data abort in Hyp mode at: 0xc067d150 [ 3.663897] unexpected HVC/SVC trap in Hyp mode at: 0xc0901dd0 The trick here is to detect if we've been through a full re-init or not by looking at HVBAR (VBAR_EL2 on arm64). This involves implementing the backend for __hyp_get_vectors in the main KVM HYP code (rather small), and checking the return value against the default one when the CPU notifier is called on CPU_PM_EXIT. Reported-by:
Andre Przywara <osp@andrep.de> Tested-by:
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Takuya Yoshikawa authored
No need to scan the entire VCPU array. Signed-off-by:
Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp> Signed-off-by:
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- 26 Feb, 2014 2 commits
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Michael Mueller authored
Commit "kvm: Record the preemption status of vcpus using preempt notifiers" caused a performance regression on s390. It turned out that in the case that if a former sleeping cpu, that was woken up, this cpu is not a yield candidate since it gave up the cpu voluntarily. To retain this candiate its preempted flag is set during wakeup and interrupt delivery time. Significant performance measurement work and code analysis to solve this issue was provided by Mao Chuan Li and his team in Beijing. Signed-off-by:
Michael Mueller <mimu@linux.vnet.ibm.com> Reviewed-by:
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Michael Mueller authored
Use the arch specific function kvm_arch_vcpu_runnable() to add a further criterium to identify a suitable vcpu to yield to during undirected yield processing. Signed-off-by:
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