lwn.git/virt/kvm/kvm_main.c, branch docs-5.2a

Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

2019-03-15T22:00:28+00:00

Pull KVM updates from Paolo Bonzini: "ARM: - some cleanups - direct physical timer assignment - cache sanitization for 32-bit guests s390: - interrupt cleanup - introduction of the Guest Information Block - preparation for processor subfunctions in cpu models PPC: - bug fixes and improvements, especially related to machine checks and protection keys x86: - many, many cleanups, including removing a bunch of MMU code for unnecessary optimizations - AVIC fixes Generic: - memcg accounting" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (147 commits) kvm: vmx: fix formatting of a comment KVM: doc: Document the life cycle of a VM and its resources MAINTAINERS: Add KVM selftests to existing KVM entry Revert "KVM/MMU: Flush tlb directly in the kvm_zap_gfn_range()" KVM: PPC: Book3S: Add count cache flush parameters to kvmppc_get_cpu_char() KVM: PPC: Fix compilation when KVM is not enabled KVM: Minor cleanups for kvm_main.c KVM: s390: add debug logging for cpu model subfunctions KVM: s390: implement subfunction processor calls arm64: KVM: Fix architecturally invalid reset value for FPEXC32_EL2 KVM: arm/arm64: Remove unused timer variable KVM: PPC: Book3S: Improve KVM reference counting KVM: PPC: Book3S HV: Fix build failure without IOMMU support Revert "KVM: Eliminate extra function calls in kvm_get_dirty_log_protect()" x86: kvmguest: use TSC clocksource if invariant TSC is exposed KVM: Never start grow vCPU halt_poll_ns from value below halt_poll_ns_grow_start KVM: Expose the initial start value in grow_halt_poll_ns() as a module parameter KVM: grow_halt_poll_ns() should never shrink vCPU halt_poll_ns KVM: x86/mmu: Consolidate kvm_mmu_zap_all() and kvm_mmu_zap_mmio_sptes() KVM: x86/mmu: WARN if zapping a MMIO spte results in zapping children ...

Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2019-03-05T22:49:11+00:00

Pull RCU updates from Ingo Molnar: "The main RCU related changes in this cycle were: - Additional cleanups after RCU flavor consolidation - Grace-period forward-progress cleanups and improvements - Documentation updates - Miscellaneous fixes - spin_is_locked() conversions to lockdep - SPDX changes to RCU source and header files - SRCU updates - Torture-test updates, including nolibc updates and moving nolibc to tools/include" * 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (71 commits) locking/locktorture: Convert to SPDX license identifier linux/torture: Convert to SPDX license identifier torture: Convert to SPDX license identifier linux/srcu: Convert to SPDX license identifier linux/rcutree: Convert to SPDX license identifier linux/rcutiny: Convert to SPDX license identifier linux/rcu_sync: Convert to SPDX license identifier linux/rcu_segcblist: Convert to SPDX license identifier linux/rcupdate: Convert to SPDX license identifier linux/rcu_node_tree: Convert to SPDX license identifier rcu/update: Convert to SPDX license identifier rcu/tree: Convert to SPDX license identifier rcu/tiny: Convert to SPDX license identifier rcu/sync: Convert to SPDX license identifier rcu/srcu: Convert to SPDX license identifier rcu/rcutorture: Convert to SPDX license identifier rcu/rcu_segcblist: Convert to SPDX license identifier rcu/rcuperf: Convert to SPDX license identifier rcu/rcu.h: Convert to SPDX license identifier RCU/torture.txt: Remove section MODULE PARAMETERS ...

kvm: properly check debugfs dentry before using it

2019-02-28T16:57:32+00:00

debugfs can now report an error code if something went wrong instead of just NULL. So if the return value is to be used as a "real" dentry, it needs to be checked if it is an error before dereferencing it. This is now happening because of ff9fb72bc077 ("debugfs: return error values, not NULL"). syzbot has found a way to trigger multiple debugfs files attempting to be created, which fails, and then the error code gets passed to dentry_path_raw() which obviously does not like it. Reported-by: Eric Biggers Reported-and-tested-by: syzbot+7857962b4d45e602b8ad@syzkaller.appspotmail.com Cc: "Radim Krčmář" Cc: kvm@vger.kernel.org Acked-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman Signed-off-by: Linus Torvalds

KVM: Minor cleanups for kvm_main.c

2019-02-22T16:43:57+00:00

This patch contains two minor cleanups: firstly it puts exported symbol for kvm_io_bus_write() by following the function definition; secondly it removes a redundant blank line. Signed-off-by: Leo Yan Signed-off-by: Paolo Bonzini

Revert "KVM: Eliminate extra function calls in kvm_get_dirty_log_protect()"

2019-02-20T21:48:52+00:00

The value of "dirty_bitmap[i]" is already check before setting its value to mask. The following check of "mask" is redundant. The check of "mask" was introduced by commit 58d2930f4ee3 ("KVM: Eliminate extra function calls in kvm_get_dirty_log_protect()"), revert it. Signed-off-by: Lan Tianyu Signed-off-by: Paolo Bonzini

KVM: Never start grow vCPU halt_poll_ns from value below halt_poll_ns_grow_start

2019-02-20T21:48:51+00:00

grow_halt_poll_ns() have a strange behaviour in case (vcpu->halt_poll_ns != 0) && (vcpu->halt_poll_ns < halt_poll_ns_grow_start). In this case, vcpu->halt_poll_ns will be multiplied by grow factor (halt_poll_ns_grow) which will require several grow iteration in order to reach a value bigger than halt_poll_ns_grow_start. This means that growing vcpu->halt_poll_ns from value of 0 is slower than growing it from a positive value less than halt_poll_ns_grow_start. Which is misleading and inaccurate. Fix issue by changing grow_halt_poll_ns() to set vcpu->halt_poll_ns to halt_poll_ns_grow_start in any case that (vcpu->halt_poll_ns < halt_poll_ns_grow_start). Regardless if vcpu->halt_poll_ns is 0. use READ_ONCE to get a consistent number for all cases. Reviewed-by: Boris Ostrovsky Reviewed-by: Liran Alon Signed-off-by: Nir Weiner Signed-off-by: Paolo Bonzini

KVM: Expose the initial start value in grow_halt_poll_ns() as a module parameter

2019-02-20T21:48:50+00:00

The hard-coded value 10000 in grow_halt_poll_ns() stands for the initial start value when raising up vcpu->halt_poll_ns. It actually sets the first timeout to the first polling session. This value has significant effect on how tolerant we are to outliers. On the standard case, higher value is better - we will spend more time in the polling busyloop, handle events/interrupts faster and result in better performance. But on outliers it puts us in a busy loop that does nothing. Even if the shrink factor is zero, we will still waste time on the first iteration. The optimal value changes between different workloads. It depends on outliers rate and polling sessions length. As this value has significant effect on the dynamic halt-polling algorithm, it should be configurable and exposed. Reviewed-by: Boris Ostrovsky Reviewed-by: Liran Alon Signed-off-by: Nir Weiner Signed-off-by: Paolo Bonzini

KVM: grow_halt_poll_ns() should never shrink vCPU halt_poll_ns

2019-02-20T21:48:50+00:00

grow_halt_poll_ns() have a strange behavior in case (halt_poll_ns_grow == 0) && (vcpu->halt_poll_ns != 0). In this case, vcpu->halt_pol_ns will be set to zero. That results in shrinking instead of growing. Fix issue by changing grow_halt_poll_ns() to not modify vcpu->halt_poll_ns in case halt_poll_ns_grow is zero Reviewed-by: Boris Ostrovsky Reviewed-by: Liran Alon Signed-off-by: Nir Weiner Suggested-by: Liran Alon Signed-off-by: Paolo Bonzini

KVM: Move the memslot update in-progress flag to bit 63

2019-02-20T21:48:37+00:00

...now that KVM won't explode by moving it out of bit 0. Using bit 63 eliminates the need to jump over bit 0, e.g. when calculating a new memslots generation or when propagating the memslots generation to an MMIO spte. Signed-off-by: Sean Christopherson Signed-off-by: Paolo Bonzini

KVM: Remove the hack to trigger memslot generation wraparound

2019-02-20T21:48:36+00:00

x86 captures a subset of the memslot generation (19 bits) in its MMIO sptes so that it can expedite emulated MMIO handling by checking only the releveant spte, i.e. doesn't need to do a full page fault walk. Because the MMIO sptes capture only 19 bits (due to limited space in the sptes), there is a non-zero probability that the MMIO generation could wrap, e.g. after 500k memslot updates. Since normal usage is extremely unlikely to result in 500k memslot updates, a hack was added by commit 69c9ea93eaea ("KVM: MMU: init kvm generation close to mmio wrap-around value") to offset the MMIO generation in order to trigger a wraparound, e.g. after 150 memslot updates. When separate memslot generation sequences were assigned to each address space, commit 00f034a12fdd ("KVM: do not bias the generation number in kvm_current_mmio_generation") moved the offset logic into the initialization of the memslot generation itself so that the per-address space bit(s) were not dropped/corrupted by the MMIO shenanigans. Remove the offset hack for three reasons: - While it does exercise x86's kvm_mmu_invalidate_mmio_sptes(), simply wrapping the generation doesn't actually test the interesting case of having stale MMIO sptes with the new generation number, e.g. old sptes with a generation number of 0. - Triggering kvm_mmu_invalidate_mmio_sptes() prematurely makes its performance rather important since the probability of invalidating MMIO sptes jumps from "effectively never" to "fairly likely". This limits what can be done in future patches, e.g. to simplify the invalidation code, as doing so without proper caution could lead to a noticeable performance regression. - Forcing the memslots generation, which is a 64-bit number, to wrap prevents KVM from assuming the memslots generation will never wrap. This in turn prevents KVM from using an arbitrary bit for the "update in-progress" flag, e.g. using bit 63 would immediately collide with using a large value as the starting generation number. The "update in-progress" flag is effectively forced into bit 0 so that it's (subtly) taken into account when incrementing the generation. Signed-off-by: Sean Christopherson Signed-off-by: Paolo Bonzini