lwn.git/arch/s390/include/asm/kvm_host.h, branch v5.10-rc2

Merge tag 'kvm-s390-next-5.9-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into kvm-next-5.6

2020-08-03T18:19:13+00:00

KVM: s390: Enhancement for 5.9 - implement diagnose 318

s390/kvm: diagnose 0x318 sync and reset

2020-06-23T08:55:33+00:00

DIAGNOSE 0x318 (diag318) sets information regarding the environment the VM is running in (Linux, z/VM, etc) and is observed via firmware/service events. This is a privileged s390x instruction that must be intercepted by SIE. Userspace handles the instruction as well as migration. Data is communicated via VCPU register synchronization. The Control Program Name Code (CPNC) is stored in the SIE block. The CPNC along with the Control Program Version Code (CPVC) are stored in the kvm_vcpu_arch struct. This data is reset on load normal and clear resets. Signed-off-by: Collin Walling Reviewed-by: Janosch Frank Acked-by: Cornelia Huck Reviewed-by: David Hildenbrand Link: https://lore.kernel.org/r/20200622154636.5499-3-walling@linux.ibm.com [borntraeger@de.ibm.com: fix sync_reg position] Signed-off-by: Christian Borntraeger

KVM: s390: reduce number of IO pins to 1

2020-06-18T07:48:19+00:00

The current number of KVM_IRQCHIP_NUM_PINS results in an order 3 allocation (32kb) for each guest start/restart. This can result in OOM killer activity even with free swap when the memory is fragmented enough: kernel: qemu-system-s39 invoked oom-killer: gfp_mask=0x440dc0(GFP_KERNEL_ACCOUNT|__GFP_COMP|__GFP_ZERO), order=3, oom_score_adj=0 kernel: CPU: 1 PID: 357274 Comm: qemu-system-s39 Kdump: loaded Not tainted 5.4.0-29-generic #33-Ubuntu kernel: Hardware name: IBM 8562 T02 Z06 (LPAR) kernel: Call Trace: kernel: ([<00000001f848fe2a>] show_stack+0x7a/0xc0) kernel: [<00000001f8d3437a>] dump_stack+0x8a/0xc0 kernel: [<00000001f8687032>] dump_header+0x62/0x258 kernel: [<00000001f8686122>] oom_kill_process+0x172/0x180 kernel: [<00000001f8686abe>] out_of_memory+0xee/0x580 kernel: [<00000001f86e66b8>] __alloc_pages_slowpath+0xd18/0xe90 kernel: [<00000001f86e6ad4>] __alloc_pages_nodemask+0x2a4/0x320 kernel: [<00000001f86b1ab4>] kmalloc_order+0x34/0xb0 kernel: [<00000001f86b1b62>] kmalloc_order_trace+0x32/0xe0 kernel: [<00000001f84bb806>] kvm_set_irq_routing+0xa6/0x2e0 kernel: [<00000001f84c99a4>] kvm_arch_vm_ioctl+0x544/0x9e0 kernel: [<00000001f84b8936>] kvm_vm_ioctl+0x396/0x760 kernel: [<00000001f875df66>] do_vfs_ioctl+0x376/0x690 kernel: [<00000001f875e304>] ksys_ioctl+0x84/0xb0 kernel: [<00000001f875e39a>] __s390x_sys_ioctl+0x2a/0x40 kernel: [<00000001f8d55424>] system_call+0xd8/0x2c8 As far as I can tell s390x does not use the iopins as we bail our for anything other than KVM_IRQ_ROUTING_S390_ADAPTER and the chip/pin is only used for KVM_IRQ_ROUTING_IRQCHIP. So let us use a small number to reduce the memory footprint. Signed-off-by: Christian Borntraeger Reviewed-by: Cornelia Huck Reviewed-by: David Hildenbrand Link: https://lore.kernel.org/r/20200617083620.5409-1-borntraeger@de.ibm.com

KVM: async_pf: Inject 'page ready' event only if 'page not present' was previously injected

2020-06-11T16:35:19+00:00

'Page not present' event may or may not get injected depending on guest's state. If the event wasn't injected, there is no need to inject the corresponding 'page ready' event as the guest may get confused. E.g. Linux thinks that the corresponding 'page not present' event wasn't delivered *yet* and allocates a 'dummy entry' for it. This entry is never freed. Note, 'wakeup all' events have no corresponding 'page not present' event and always get injected. s390 seems to always be able to inject 'page not present', the change is effectively a nop. Suggested-by: Vivek Goyal Signed-off-by: Vitaly Kuznetsov Message-Id: <20200610175532.779793-2-vkuznets@redhat.com> Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=208081 Signed-off-by: Paolo Bonzini

KVM: x86: acknowledgment mechanism for async pf page ready notifications

2020-06-01T08:26:08+00:00

If two page ready notifications happen back to back the second one is not delivered and the only mechanism we currently have is kvm_check_async_pf_completion() check in vcpu_run() loop. The check will only be performed with the next vmexit when it happens and in some cases it may take a while. With interrupt based page ready notification delivery the situation is even worse: unlike exceptions, interrupts are not handled immediately so we must check if the slot is empty. This is slow and unnecessary. Introduce dedicated MSR_KVM_ASYNC_PF_ACK MSR to communicate the fact that the slot is free and host should check its notification queue. Mandate using it for interrupt based 'page ready' APF event delivery. As kvm_check_async_pf_completion() is going away from vcpu_run() we need a way to communicate the fact that vcpu->async_pf.done queue has transitioned from empty to non-empty state. Introduce kvm_arch_async_page_present_queued() and KVM_REQ_APF_READY to do the job. Signed-off-by: Vitaly Kuznetsov Message-Id: <20200525144125.143875-7-vkuznets@redhat.com> Signed-off-by: Paolo Bonzini

KVM: rename kvm_arch_can_inject_async_page_present() to kvm_arch_can_dequeue_async_page_present()

2020-06-01T08:26:07+00:00

An innocent reader of the following x86 KVM code: bool kvm_arch_can_inject_async_page_present(struct kvm_vcpu *vcpu) { if (!(vcpu->arch.apf.msr_val & KVM_ASYNC_PF_ENABLED)) return true; ... may get very confused: if APF mechanism is not enabled, why do we report that we 'can inject async page present'? In reality, upon injection kvm_arch_async_page_present() will check the same condition again and, in case APF is disabled, will just drop the item. This is fine as the guest which deliberately disabled APF doesn't expect to get any APF notifications. Rename kvm_arch_can_inject_async_page_present() to kvm_arch_can_dequeue_async_page_present() to make it clear what we are checking: if the item can be dequeued (meaning either injected or just dropped). On s390 kvm_arch_can_inject_async_page_present() always returns 'true' so the rename doesn't matter much. Signed-off-by: Vitaly Kuznetsov Message-Id: <20200525144125.143875-4-vkuznets@redhat.com> Signed-off-by: Paolo Bonzini

kvm: add halt-polling cpu usage stats

2020-05-15T16:26:26+00:00

Two new stats for exposing halt-polling cpu usage: halt_poll_success_ns halt_poll_fail_ns Thus sum of these 2 stats is the total cpu time spent polling. "success" means the VCPU polled until a virtual interrupt was delivered. "fail" means the VCPU had to schedule out (either because the maximum poll time was reached or it needed to yield the CPU). To avoid touching every arch's kvm_vcpu_stat struct, only update and export halt-polling cpu usage stats if we're on x86. Exporting cpu usage as a u64 and in nanoseconds means we will overflow at ~500 years, which seems reasonably large. Signed-off-by: David Matlack Signed-off-by: Jon Cargille Reviewed-by: Jim Mattson Message-Id: <20200508182240.68440-1-jcargill@google.com> Signed-off-by: Paolo Bonzini

Merge tag 'kvm-s390-next-5.7-2' of git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into HEAD

2020-03-26T09:58:49+00:00

KVM: s390: cleanups for 5.7 - mark sie control block as 512 byte aligned - use fallthrough;

KVM: s390: mark sie block as 512 byte aligned

2020-03-23T17:30:33+00:00

The sie block must be aligned to 512 bytes. Mark it as such. Signed-off-by: Christian Borntraeger Reviewed-by: David Hildenbrand

Merge tag 'kvm-s390-next-5.7-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into HEAD

2020-03-16T17:19:34+00:00

KVM: s390: Features and Enhancements for 5.7 part1 1. Allow to disable gisa 2. protected virtual machines Protected VMs (PVM) are KVM VMs, where KVM can't access the VM's state like guest memory and guest registers anymore. Instead the PVMs are mostly managed by a new entity called Ultravisor (UV), which provides an API, so KVM and the PV can request management actions. PVMs are encrypted at rest and protected from hypervisor access while running. They switch from a normal operation into protected mode, so we can still use the standard boot process to load a encrypted blob and then move it into protected mode. Rebooting is only possible by passing through the unprotected/normal mode and switching to protected again. One mm related patch will go via Andrews mm tree ( mm/gup/writeback: add callbacks for inaccessible pages)