user/sven/linux.git/include/linux/kvm_host.h, branch v4.14.136

KVM: fix spectrev1 gadgets

2019-05-16T17:42:22Z

[ Upstream commit 1d487e9bf8ba66a7174c56a0029c54b1eca8f99c ] These were found with smatch, and then generalized when applicable. Signed-off-by: Paolo Bonzini Signed-off-by: Sasha Levin

KVM: Call kvm_arch_memslots_updated() before updating memslots

2019-03-23T13:35:31Z

commit 152482580a1b0accb60676063a1ac57b2d12daf6 upstream. kvm_arch_memslots_updated() is at this point in time an x86-specific hook for handling MMIO generation wraparound. x86 stashes 19 bits of the memslots generation number in its MMIO sptes in order to avoid full page fault walks for repeat faults on emulated MMIO addresses. Because only 19 bits are used, wrapping the MMIO generation number is possible, if unlikely. kvm_arch_memslots_updated() alerts x86 that the generation has changed so that it can invalidate all MMIO sptes in case the effective MMIO generation has wrapped so as to avoid using a stale spte, e.g. a (very) old spte that was created with generation==0. Given that the purpose of kvm_arch_memslots_updated() is to prevent consuming stale entries, it needs to be called before the new generation is propagated to memslots. Invalidating the MMIO sptes after updating memslots means that there is a window where a vCPU could dereference the new memslots generation, e.g. 0, and incorrectly reuse an old MMIO spte that was created with (pre-wrap) generation==0. Fixes: e59dbe09f8e6 ("KVM: Introduce kvm_arch_memslots_updated()") Cc: Signed-off-by: Sean Christopherson Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman

kvm: Change offset in kvm_write_guest_offset_cached to unsigned

2019-02-12T18:46:07Z

[ Upstream commit 7a86dab8cf2f0fdf508f3555dddfc236623bff60 ] Since the offset is added directly to the hva from the gfn_to_hva_cache, a negative offset could result in an out of bounds write. The existing BUG_ON only checks for addresses beyond the end of the gfn_to_hva_cache, not for addresses before the start of the gfn_to_hva_cache. Note that all current call sites have non-negative offsets. Fixes: 4ec6e8636256 ("kvm: Introduce kvm_write_guest_offset_cached()") Reported-by: Cfir Cohen Signed-off-by: Jim Mattson Reviewed-by: Cfir Cohen Reviewed-by: Peter Shier Reviewed-by: Krish Sadhukhan Reviewed-by: Sean Christopherson Signed-off-by: Radim Krčmář Signed-off-by: Sasha Levin

x86,kvm: move qemu/guest FPU switching out to vcpu_run

2019-01-16T21:07:09Z

commit f775b13eedee2f7f3c6fdd4e90fb79090ce5d339 upstream. Currently, every time a VCPU is scheduled out, the host kernel will first save the guest FPU/xstate context, then load the qemu userspace FPU context, only to then immediately save the qemu userspace FPU context back to memory. When scheduling in a VCPU, the same extraneous FPU loads and saves are done. This could be avoided by moving from a model where the guest FPU is loaded and stored with preemption disabled, to a model where the qemu userspace FPU is swapped out for the guest FPU context for the duration of the KVM_RUN ioctl. This is done under the VCPU mutex, which is also taken when other tasks inspect the VCPU FPU context, so the code should already be safe for this change. That should come as no surprise, given that s390 already has this optimization. This can fix a bug where KVM calls get_user_pages while owning the FPU, and the file system ends up requesting the FPU again: [258270.527947] __warn+0xcb/0xf0 [258270.527948] warn_slowpath_null+0x1d/0x20 [258270.527951] kernel_fpu_disable+0x3f/0x50 [258270.527953] __kernel_fpu_begin+0x49/0x100 [258270.527955] kernel_fpu_begin+0xe/0x10 [258270.527958] crc32c_pcl_intel_update+0x84/0xb0 [258270.527961] crypto_shash_update+0x3f/0x110 [258270.527968] crc32c+0x63/0x8a [libcrc32c] [258270.527975] dm_bm_checksum+0x1b/0x20 [dm_persistent_data] [258270.527978] node_prepare_for_write+0x44/0x70 [dm_persistent_data] [258270.527985] dm_block_manager_write_callback+0x41/0x50 [dm_persistent_data] [258270.527988] submit_io+0x170/0x1b0 [dm_bufio] [258270.527992] __write_dirty_buffer+0x89/0x90 [dm_bufio] [258270.527994] __make_buffer_clean+0x4f/0x80 [dm_bufio] [258270.527996] __try_evict_buffer+0x42/0x60 [dm_bufio] [258270.527998] dm_bufio_shrink_scan+0xc0/0x130 [dm_bufio] [258270.528002] shrink_slab.part.40+0x1f5/0x420 [258270.528004] shrink_node+0x22c/0x320 [258270.528006] do_try_to_free_pages+0xf5/0x330 [258270.528008] try_to_free_pages+0xe9/0x190 [258270.528009] __alloc_pages_slowpath+0x40f/0xba0 [258270.528011] __alloc_pages_nodemask+0x209/0x260 [258270.528014] alloc_pages_vma+0x1f1/0x250 [258270.528017] do_huge_pmd_anonymous_page+0x123/0x660 [258270.528021] handle_mm_fault+0xfd3/0x1330 [258270.528025] __get_user_pages+0x113/0x640 [258270.528027] get_user_pages+0x4f/0x60 [258270.528063] __gfn_to_pfn_memslot+0x120/0x3f0 [kvm] [258270.528108] try_async_pf+0x66/0x230 [kvm] [258270.528135] tdp_page_fault+0x130/0x280 [kvm] [258270.528149] kvm_mmu_page_fault+0x60/0x120 [kvm] [258270.528158] handle_ept_violation+0x91/0x170 [kvm_intel] [258270.528162] vmx_handle_exit+0x1ca/0x1400 [kvm_intel] No performance changes were detected in quick ping-pong tests on my 4 socket system, which is expected since an FPU+xstate load is on the order of 0.1us, while ping-ponging between CPUs is on the order of 20us, and somewhat noisy. Cc: stable@vger.kernel.org Signed-off-by: Rik van Riel Suggested-by: Christian Borntraeger Signed-off-by: Paolo Bonzini [Fixed a bug where reset_vcpu called put_fpu without preceding load_fpu, which happened inside from KVM_CREATE_VCPU ioctl. - Radim] Signed-off-by: Radim Krčmář Signed-off-by: Greg Kroah-Hartman

KVM: Extend MAX_IRQ_ROUTES to 4096 for all archs

2018-06-20T19:02:57Z

[ Upstream commit ddc9cfb79c1096a0855839631c091aa7e9602052 ] Our virtual machines make use of device assignment by configuring 12 NVMe disks for high I/O performance. Each NVMe device has 129 MSI-X Table entries: Capabilities: [50] MSI-X: Enable+ Count=129 Masked-Vector table: BAR=0 offset=00002000 The windows virtual machines fail to boot since they will map the number of MSI-table entries that the NVMe hardware reported to the bus to msi routing table, this will exceed the 1024. This patch extends MAX_IRQ_ROUTES to 4096 for all archs, in the future this might be extended again if needed. Reviewed-by: Cornelia Huck Cc: Paolo Bonzini Cc: Radim KrÄmÃ¡Å™ Cc: Cornelia Huck Cc: Christian Borntraeger Signed-off-by: Wanpeng Li Signed-off-by: Tonny Lu Signed-off-by: Paolo Bonzini Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

kvm: fix warning for CONFIG_HAVE_KVM_EVENTFD builds

2018-05-30T05:52:02Z

[ Upstream commit 076467490b8176eb96eddc548a14d4135c7b5852 ] Move the kvm_arch_irq_routing_update() prototype outside of ifdef CONFIG_HAVE_KVM_EVENTFD guards to fix the following sparse warning: arch/s390/kvm/../../../virt/kvm/irqchip.c:171:28: warning: symbol 'kvm_arch_irq_routing_update' was not declared. Should it be static? Signed-off-by: Sebastian Ott Acked-by: Christian Borntraeger Signed-off-by: Paolo Bonzini Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

KVM: Let KVM_SET_SIGNAL_MASK work as advertised

2018-02-03T16:39:06Z

[ Upstream commit 20b7035c66bacc909ae3ffe92c1a1ea7db99fe4f ] KVM API says for the signal mask you set via KVM_SET_SIGNAL_MASK, that "any unblocked signal received [...] will cause KVM_RUN to return with -EINTR" and that "the signal will only be delivered if not blocked by the original signal mask". This, however, is only true, when the calling task has a signal handler registered for a signal. If not, signal evaluation is short-circuited for SIG_IGN and SIG_DFL, and the signal is either ignored without KVM_RUN returning or the whole process is terminated. Make KVM_SET_SIGNAL_MASK behave as advertised by utilizing logic similar to that in do_sigtimedwait() to avoid short-circuiting of signals. Signed-off-by: Jan H. SchÃ¶nherr Signed-off-by: Paolo Bonzini Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

KVM: add spinlock optimization framework

2017-08-08T08:57:43Z

If a vcpu exits due to request a user mode spinlock, then the spinlock-holder may be preempted in user mode or kernel mode. (Note that not all architectures trap spin loops in user mode, only AMD x86 and ARM/ARM64 currently do). But if a vcpu exits in kernel mode, then the holder must be preempted in kernel mode, so we should choose a vcpu in kernel mode as a more likely candidate for the lock holder. This introduces kvm_arch_vcpu_in_kernel() to decide whether the vcpu is in kernel-mode when it's preempted. kvm_vcpu_on_spin's new argument says the same of the spinning VCPU. Signed-off-by: Longpeng(Mike) Signed-off-by: Paolo Bonzini

KVM: nVMX: get rid of nested_get_page()

2017-08-07T13:27:00Z

nested_get_page() just sounds confusing. All we want is a page from G1. This is even unrelated to nested. Let's introduce kvm_vcpu_gpa_to_page() so we don't get too lengthy lines. Reviewed-by: Paolo Bonzini Signed-off-by: David Hildenbrand Signed-off-by: Radim Krčmář [Squash pasto fix from Wanpeng Li. - Paolo] Signed-off-by: Paolo Bonzini

KVM: avoid using rcu_dereference_protected

2017-08-02T20:41:02Z

During teardown, accesses to memslots and buses are using rcu_dereference_protected with an always-true condition because these accesses are done outside the usual mutexes. This is because the last reference is gone and there cannot be any concurrent modifications, but rcu_dereference_protected is ugly and unobvious. Instead, check the refcount in kvm_get_bus and __kvm_memslots. Signed-off-by: Paolo Bonzini Signed-off-by: Radim Krčmář