linux/Documentation/virt, branch v6.2

Merge tag 'kvmarm-fixes-6.2-3' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

2023-02-04T13:57:43Z

KVM/arm64 fixes for 6.2, take #3 - Yet another fix for non-CPU accesses to the memory backing the VGICv3 subsystem - A set of fixes for the setlftest checking for the S1PTW behaviour after the fix that went in ealier in the cycle

KVM: arm64: Allow no running vcpu on saving vgic3 pending table

2023-01-29T18:46:11Z

We don't have a running VCPU context to save vgic3 pending table due to KVM_DEV_ARM_VGIC_{GRP_CTRL, SAVE_PENDING_TABLES} command on KVM device "kvm-arm-vgic-v3". The unknown case is caught by kvm-unit-tests. # ./kvm-unit-tests/tests/its-pending-migration WARNING: CPU: 120 PID: 7973 at arch/arm64/kvm/../../../virt/kvm/kvm_main.c:3325 \ mark_page_dirty_in_slot+0x60/0xe0 : mark_page_dirty_in_slot+0x60/0xe0 __kvm_write_guest_page+0xcc/0x100 kvm_write_guest+0x7c/0xb0 vgic_v3_save_pending_tables+0x148/0x2a0 vgic_set_common_attr+0x158/0x240 vgic_v3_set_attr+0x4c/0x5c kvm_device_ioctl+0x100/0x160 __arm64_sys_ioctl+0xa8/0xf0 invoke_syscall.constprop.0+0x7c/0xd0 el0_svc_common.constprop.0+0x144/0x160 do_el0_svc+0x34/0x60 el0_svc+0x3c/0x1a0 el0t_64_sync_handler+0xb4/0x130 el0t_64_sync+0x178/0x17c Use vgic_write_guest_lock() to save vgic3 pending table. Reported-by: Zenghui Yu Signed-off-by: Gavin Shan Reviewed-by: Oliver Upton Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20230126235451.469087-5-gshan@redhat.com

KVM: arm64: Allow no running vcpu on restoring vgic3 LPI pending status

2023-01-29T18:46:11Z

We don't have a running VCPU context to restore vgic3 LPI pending status due to command KVM_DEV_ARM_{VGIC_GRP_CTRL, ITS_RESTORE_TABLES} on KVM device "kvm-arm-vgic-its". Use vgic_write_guest_lock() to restore vgic3 LPI pending status. Signed-off-by: Gavin Shan Reviewed-by: Oliver Upton Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20230126235451.469087-4-gshan@redhat.com

KVM: x86/xen: Avoid deadlock by adding kvm->arch.xen.xen_lock leaf node lock

2023-01-11T22:45:58Z

In commit 14243b387137a ("KVM: x86/xen: Add KVM_IRQ_ROUTING_XEN_EVTCHN and event channel delivery") the clever version of me left some helpful notes for those who would come after him: /* * For the irqfd workqueue, using the main kvm->lock mutex is * fine since this function is invoked from kvm_set_irq() with * no other lock held, no srcu. In future if it will be called * directly from a vCPU thread (e.g. on hypercall for an IPI) * then it may need to switch to using a leaf-node mutex for * serializing the shared_info mapping. */ mutex_lock(&kvm->lock); In commit 2fd6df2f2b47 ("KVM: x86/xen: intercept EVTCHNOP_send from guests") the other version of me ran straight past that comment without reading it, and introduced a potential deadlock by taking vcpu->mutex and kvm->lock in the wrong order. Solve this as originally suggested, by adding a leaf-node lock in the Xen state rather than using kvm->lock for it. Fixes: 2fd6df2f2b47 ("KVM: x86/xen: intercept EVTCHNOP_send from guests") Signed-off-by: David Woodhouse Message-Id: <20230111180651.14394-4-dwmw2@infradead.org> [Rebase, add docs. - Paolo] Signed-off-by: Paolo Bonzini

Merge tag 'kvmarm-fixes-6.2-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into kvm-master

2023-01-11T18:31:53Z

KVM/arm64 fixes for 6.2, take #1 - Fix the PMCR_EL0 reset value after the PMU rework - Correctly handle S2 fault triggered by a S1 page table walk by not always classifying it as a write, as this breaks on R/O memslots - Document why we cannot exit with KVM_EXIT_MMIO when taking a write fault from a S1 PTW on a R/O memslot - Put the Apple M2 on the naughty step for not being able to correctly implement the vgic SEIS feature, just liek the M1 before it - Reviewer updates: Alex is stepping down, replaced by Zenghui

Documentation: kvm: fix SRCU locking order docs

2023-01-11T18:31:33Z

kvm->srcu is taken in KVM_RUN and several other vCPU ioctls, therefore vcpu->mutex is susceptible to the same deadlock that is documented for kvm->slots_lock. The same holds for kvm->lock, since kvm->lock is held outside vcpu->mutex. Fix the documentation and rearrange it to highlight the difference between these locks and kvm->slots_arch_lock, and how kvm->slots_arch_lock can be useful while processing a vmexit. Signed-off-by: Paolo Bonzini

KVM: x86: Do not return host topology information from KVM_GET_SUPPORTED_CPUID

2023-01-09T10:35:21Z

Passing the host topology to the guest is almost certainly wrong and will confuse the scheduler. In addition, several fields of these CPUID leaves vary on each processor; it is simply impossible to return the right values from KVM_GET_SUPPORTED_CPUID in such a way that they can be passed to KVM_SET_CPUID2. The values that will most likely prevent confusion are all zeroes. Userspace will have to override it anyway if it wishes to present a specific topology to the guest. Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini

Merge branch kvm-arm64/s1ptw-write-fault into kvmarm-master/fixes

2023-01-05T15:25:54Z

* kvm-arm64/s1ptw-write-fault: : . : Fix S1PTW fault handling that was until then always taken : as a write. From the cover letter: : : `Recent developments on the EFI front have resulted in guests that : simply won't boot if the page tables are in a read-only memslot and : that you're a bit unlucky in the way S2 gets paged in... The core : issue is related to the fact that we treat a S1PTW as a write, which : is close enough to what needs to be done. Until to get to RO memslots. : : The first patch fixes this and is definitely a stable candidate. It : splits the faulting of page tables in two steps (RO translation fault, : followed by a writable permission fault -- should it even happen). : The second one documents the slightly odd behaviour of PTW writes to : RO memslot, which do not result in a KVM_MMIO exit. The last patch is : totally optional, only tangentially related, and randomly repainting : stuff (maybe that's contagious, who knows)." : : . KVM: arm64: Convert FSC_* over to ESR_ELx_FSC_* KVM: arm64: Document the behaviour of S1PTW faults on RO memslots KVM: arm64: Fix S1PTW handling on RO memslots Signed-off-by: Marc Zyngier

KVM: arm64: Document the behaviour of S1PTW faults on RO memslots

2023-01-03T10:01:52Z

Although the KVM API says that a write to a RO memslot must result in a KVM_EXIT_MMIO describing the write, the arm64 architecture doesn't provide the *data* written by a Stage-1 page table walk (we only get the address). Since there isn't much userspace can do with so little information anyway, document the fact that such an access results in a guest exception, not an exit. This is consistent with the guest being terminally broken anyway. Reviewed-by: Oliver Upton Signed-off-by: Marc Zyngier

Merge branch 'kvm-late-6.1-fixes' into HEAD

2022-12-28T12:19:14Z

x86: * several fixes to nested VMX execution controls * fixes and clarification to the documentation for Xen emulation * do not unnecessarily release a pmu event with zero period * MMU fixes * fix Coverity warning in kvm_hv_flush_tlb() selftests: * fixes for the ucall mechanism in selftests * other fixes mostly related to compilation with clang