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2020-07-08KVM: async_pf: change kvm_setup_async_pf()/kvm_arch_setup_async_pf() return ↵Vitaly Kuznetsov
type to bool Unlike normal 'int' functions returning '0' on success, kvm_setup_async_pf()/ kvm_arch_setup_async_pf() return '1' when a job to handle page fault asynchronously was scheduled and '0' otherwise. To avoid the confusion change return type to 'bool'. No functional change intended. Suggested-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Message-Id: <20200615121334.91300-1-vkuznets@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-07-02kvm: use more precise cast and do not drop __userPaolo Bonzini
Sparse complains on a call to get_compat_sigset, fix it. The "if" right above explains that sigmask_arg->sigset is basically a compat_sigset_t. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-06-12Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds
Pull more KVM updates from Paolo Bonzini: "The guest side of the asynchronous page fault work has been delayed to 5.9 in order to sync with Thomas's interrupt entry rework, but here's the rest of the KVM updates for this merge window. MIPS: - Loongson port PPC: - Fixes ARM: - Fixes x86: - KVM_SET_USER_MEMORY_REGION optimizations - Fixes - Selftest fixes" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (62 commits) KVM: x86: do not pass poisoned hva to __kvm_set_memory_region KVM: selftests: fix sync_with_host() in smm_test KVM: async_pf: Inject 'page ready' event only if 'page not present' was previously injected KVM: async_pf: Cleanup kvm_setup_async_pf() kvm: i8254: remove redundant assignment to pointer s KVM: x86: respect singlestep when emulating instruction KVM: selftests: Don't probe KVM_CAP_HYPERV_ENLIGHTENED_VMCS when nested VMX is unsupported KVM: selftests: do not substitute SVM/VMX check with KVM_CAP_NESTED_STATE check KVM: nVMX: Consult only the "basic" exit reason when routing nested exit KVM: arm64: Move hyp_symbol_addr() to kvm_asm.h KVM: arm64: Synchronize sysreg state on injecting an AArch32 exception KVM: arm64: Make vcpu_cp1x() work on Big Endian hosts KVM: arm64: Remove host_cpu_context member from vcpu structure KVM: arm64: Stop sparse from moaning at __hyp_this_cpu_ptr KVM: arm64: Handle PtrAuth traps early KVM: x86: Unexport x86_fpu_cache and make it static KVM: selftests: Ignore KVM 5-level paging support for VM_MODE_PXXV48_4K KVM: arm64: Save the host's PtrAuth keys in non-preemptible context KVM: arm64: Stop save/restoring ACTLR_EL1 KVM: arm64: Add emulation for 32bit guests accessing ACTLR2 ...
2020-06-11KVM: async_pf: Inject 'page ready' event only if 'page not present' was ↵Vitaly Kuznetsov
previously injected '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 <vgoyal@redhat.com> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Message-Id: <20200610175532.779793-2-vkuznets@redhat.com> Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=208081 Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-06-11KVM: async_pf: Cleanup kvm_setup_async_pf()Vitaly Kuznetsov
schedule_work() returns 'false' only when the work is already on the queue and this can't happen as kvm_setup_async_pf() always allocates a new one. Also, to avoid potential race, it makes sense to to schedule_work() at the very end after we've added it to the queue. While on it, do some minor cleanup. gfn_to_pfn_async() mentioned in a comment does not currently exist and, moreover, we can check kvm_is_error_hva() at the very beginning, before we try to allocate work so 'retry_sync' label can go away completely. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Message-Id: <20200610175532.779793-1-vkuznets@redhat.com> Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-06-09mmap locking API: use coccinelle to convert mmap_sem rwsem call sitesMichel Lespinasse
This change converts the existing mmap_sem rwsem calls to use the new mmap locking API instead. The change is generated using coccinelle with the following rule: // spatch --sp-file mmap_lock_api.cocci --in-place --include-headers --dir . @@ expression mm; @@ ( -init_rwsem +mmap_init_lock | -down_write +mmap_write_lock | -down_write_killable +mmap_write_lock_killable | -down_write_trylock +mmap_write_trylock | -up_write +mmap_write_unlock | -downgrade_write +mmap_write_downgrade | -down_read +mmap_read_lock | -down_read_killable +mmap_read_lock_killable | -down_read_trylock +mmap_read_trylock | -up_read +mmap_read_unlock ) -(&mm->mmap_sem) +(mm) Signed-off-by: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Reviewed-by: Laurent Dufour <ldufour@linux.ibm.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Liam Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ying Han <yinghan@google.com> Link: http://lkml.kernel.org/r/20200520052908.204642-5-walken@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-09mm: don't include asm/pgtable.h if linux/mm.h is already includedMike Rapoport
Patch series "mm: consolidate definitions of page table accessors", v2. The low level page table accessors (pXY_index(), pXY_offset()) are duplicated across all architectures and sometimes more than once. For instance, we have 31 definition of pgd_offset() for 25 supported architectures. Most of these definitions are actually identical and typically it boils down to, e.g. static inline unsigned long pmd_index(unsigned long address) { return (address >> PMD_SHIFT) & (PTRS_PER_PMD - 1); } static inline pmd_t *pmd_offset(pud_t *pud, unsigned long address) { return (pmd_t *)pud_page_vaddr(*pud) + pmd_index(address); } These definitions can be shared among 90% of the arches provided XYZ_SHIFT, PTRS_PER_XYZ and xyz_page_vaddr() are defined. For architectures that really need a custom version there is always possibility to override the generic version with the usual ifdefs magic. These patches introduce include/linux/pgtable.h that replaces include/asm-generic/pgtable.h and add the definitions of the page table accessors to the new header. This patch (of 12): The linux/mm.h header includes <asm/pgtable.h> to allow inlining of the functions involving page table manipulations, e.g. pte_alloc() and pmd_alloc(). So, there is no point to explicitly include <asm/pgtable.h> in the files that include <linux/mm.h>. The include statements in such cases are remove with a simple loop: for f in $(git grep -l "include <linux/mm.h>") ; do sed -i -e '/include <asm\/pgtable.h>/ d' $f done Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Cain <bcain@codeaurora.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chris Zankel <chris@zankel.net> Cc: "David S. Miller" <davem@davemloft.net> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Greentime Hu <green.hu@gmail.com> Cc: Greg Ungerer <gerg@linux-m68k.org> Cc: Guan Xuetao <gxt@pku.edu.cn> Cc: Guo Ren <guoren@kernel.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Helge Deller <deller@gmx.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Ley Foon Tan <ley.foon.tan@intel.com> Cc: Mark Salter <msalter@redhat.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Matt Turner <mattst88@gmail.com> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Simek <monstr@monstr.eu> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nick Hu <nickhu@andestech.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Richard Weinberger <richard@nod.at> Cc: Rich Felker <dalias@libc.org> Cc: Russell King <linux@armlinux.org.uk> Cc: Stafford Horne <shorne@gmail.com> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Vincent Chen <deanbo422@gmail.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Will Deacon <will@kernel.org> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Link: http://lkml.kernel.org/r/20200514170327.31389-1-rppt@kernel.org Link: http://lkml.kernel.org/r/20200514170327.31389-2-rppt@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-08mm/gup.c: convert to use get_user_{page|pages}_fast_only()Souptick Joarder
API __get_user_pages_fast() renamed to get_user_pages_fast_only() to align with pin_user_pages_fast_only(). As part of this we will get rid of write parameter. Instead caller will pass FOLL_WRITE to get_user_pages_fast_only(). This will not change any existing functionality of the API. All the callers are changed to pass FOLL_WRITE. Also introduce get_user_page_fast_only(), and use it in a few places that hard-code nr_pages to 1. Updated the documentation of the API. Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: John Hubbard <jhubbard@nvidia.com> Reviewed-by: Paul Mackerras <paulus@ozlabs.org> [arch/powerpc/kvm] Cc: Matthew Wilcox <willy@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Michal Suchanek <msuchanek@suse.de> Link: http://lkml.kernel.org/r/1590396812-31277-1-git-send-email-jrdr.linux@gmail.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-08KVM: x86: Fix APIC page invalidation raceEiichi Tsukata
Commit b1394e745b94 ("KVM: x86: fix APIC page invalidation") tried to fix inappropriate APIC page invalidation by re-introducing arch specific kvm_arch_mmu_notifier_invalidate_range() and calling it from kvm_mmu_notifier_invalidate_range_start. However, the patch left a possible race where the VMCS APIC address cache is updated *before* it is unmapped: (Invalidator) kvm_mmu_notifier_invalidate_range_start() (Invalidator) kvm_make_all_cpus_request(kvm, KVM_REQ_APIC_PAGE_RELOAD) (KVM VCPU) vcpu_enter_guest() (KVM VCPU) kvm_vcpu_reload_apic_access_page() (Invalidator) actually unmap page Because of the above race, there can be a mismatch between the host physical address stored in the APIC_ACCESS_PAGE VMCS field and the host physical address stored in the EPT entry for the APIC GPA (0xfee0000). When this happens, the processor will not trap APIC accesses, and will instead show the raw contents of the APIC-access page. Because Windows OS periodically checks for unexpected modifications to the LAPIC register, this will show up as a BSOD crash with BugCheck CRITICAL_STRUCTURE_CORRUPTION (109) we are currently seeing in https://bugzilla.redhat.com/show_bug.cgi?id=1751017. The root cause of the issue is that kvm_arch_mmu_notifier_invalidate_range() cannot guarantee that no additional references are taken to the pages in the range before kvm_mmu_notifier_invalidate_range_end(). Fortunately, this case is supported by the MMU notifier API, as documented in include/linux/mmu_notifier.h: * If the subsystem * can't guarantee that no additional references are taken to * the pages in the range, it has to implement the * invalidate_range() notifier to remove any references taken * after invalidate_range_start(). The fix therefore is to reload the APIC-access page field in the VMCS from kvm_mmu_notifier_invalidate_range() instead of ..._range_start(). Cc: stable@vger.kernel.org Fixes: b1394e745b94 ("KVM: x86: fix APIC page invalidation") Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=197951 Signed-off-by: Eiichi Tsukata <eiichi.tsukata@nutanix.com> Message-Id: <20200606042627.61070-1-eiichi.tsukata@nutanix.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-06-04KVM: Use vmemdup_user()Denis Efremov
Replace opencoded alloc and copy with vmemdup_user(). Signed-off-by: Denis Efremov <efremov@linux.com> Message-Id: <20200603101131.2107303-1-efremov@linux.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-06-04KVM: let kvm_destroy_vm_debugfs clean up vCPU debugfs directoriesPaolo Bonzini
After commit 63d0434 ("KVM: x86: move kvm_create_vcpu_debugfs after last failure point") we are creating the pre-vCPU debugfs files after the creation of the vCPU file descriptor. This makes it possible for userspace to reach kvm_vcpu_release before kvm_create_vcpu_debugfs has finished. The vcpu->debugfs_dentry then does not have any associated inode anymore, and this causes a NULL-pointer dereference in debugfs_create_file. The solution is simply to avoid removing the files; they are cleaned up when the VM file descriptor is closed (and that must be after KVM_CREATE_VCPU returns). We can stop storing the dentry in struct kvm_vcpu too, because it is not needed anywhere after kvm_create_vcpu_debugfs returns. Reported-by: syzbot+705f4401d5a93a59b87d@syzkaller.appspotmail.com Fixes: 63d04348371b ("KVM: x86: move kvm_create_vcpu_debugfs after last failure point") Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-06-01Merge tag 'kvmarm-5.8' of ↵Paolo Bonzini
git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD KVM/arm64 updates for Linux 5.8: - Move the arch-specific code into arch/arm64/kvm - Start the post-32bit cleanup - Cherry-pick a few non-invasive pre-NV patches
2020-06-01KVM: check userspace_addr for all memslotsPaolo Bonzini
The userspace_addr alignment and range checks are not performed for private memory slots that are prepared by KVM itself. This is unnecessary and makes it questionable to use __*_user functions to access memory later on. We also rely on the userspace address being aligned since we have an entire family of functions to map gfn to pfn. Fortunately skipping the check is completely unnecessary. Only x86 uses private memslots and their userspace_addr is obtained from vm_mmap, therefore it must be below PAGE_OFFSET. In fact, any attempt to pass an address above PAGE_OFFSET would have failed because such an address would return true for kvm_is_error_hva. Reported-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-06-01KVM: x86: acknowledgment mechanism for async pf page ready notificationsVitaly Kuznetsov
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 <vkuznets@redhat.com> Message-Id: <20200525144125.143875-7-vkuznets@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-06-01KVM: introduce kvm_read_guest_offset_cached()Vitaly Kuznetsov
We already have kvm_write_guest_offset_cached(), introduce read analogue. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Message-Id: <20200525144125.143875-5-vkuznets@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-06-01KVM: rename kvm_arch_can_inject_async_page_present() to ↵Vitaly Kuznetsov
kvm_arch_can_dequeue_async_page_present() 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 <vkuznets@redhat.com> Message-Id: <20200525144125.143875-4-vkuznets@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-06-01Revert "KVM: No need to retry for hva_to_pfn_remapped()"Paolo Bonzini
This reverts commit 5b494aea13fe9ec67365510c0d75835428cbb303. If unlocked==true then the vma pointer could be invalidated, so the 2nd follow_pfn() is potentially racy: we do need to get out and redo find_vma_intersection(). Signed-off-by: Peter Xu <peterx@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-05-16KVM: Fix spelling in code commentsFuad Tabba
Fix spelling and typos (e.g., repeated words) in comments. Signed-off-by: Fuad Tabba <tabba@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20200401140310.29701-1-tabba@google.com
2020-05-16KVM: arm64: Move virt/kvm/arm to arch/arm64Marc Zyngier
Now that the 32bit KVM/arm host is a distant memory, let's move the whole of the KVM/arm64 code into the arm64 tree. As they said in the song: Welcome Home (Sanitarium). Signed-off-by: Marc Zyngier <maz@kernel.org> Acked-by: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20200513104034.74741-1-maz@kernel.org
2020-05-15kvm: add halt-polling cpu usage statsDavid Matlack
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 <dmatlack@google.com> Signed-off-by: Jon Cargille <jcargill@google.com> Reviewed-by: Jim Mattson <jmattson@google.com> Message-Id: <20200508182240.68440-1-jcargill@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-05-15KVM: VMX: Optimize posted-interrupt delivery for timer fastpathWanpeng Li
While optimizing posted-interrupt delivery especially for the timer fastpath scenario, I measured kvm_x86_ops.deliver_posted_interrupt() to introduce substantial latency because the processor has to perform all vmentry tasks, ack the posted interrupt notification vector, read the posted-interrupt descriptor etc. This is not only slow, it is also unnecessary when delivering an interrupt to the current CPU (as is the case for the LAPIC timer) because PIR->IRR and IRR->RVI synchronization is already performed on vmentry Therefore skip kvm_vcpu_trigger_posted_interrupt in this case, and instead do vmx_sync_pir_to_irr() on the EXIT_FASTPATH_REENTER_GUEST fastpath as well. Tested-by: Haiwei Li <lihaiwei@tencent.com> Cc: Haiwei Li <lihaiwei@tencent.com> Suggested-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Wanpeng Li <wanpengli@tencent.com> Message-Id: <1588055009-12677-6-git-send-email-wanpengli@tencent.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-05-15KVM: No need to retry for hva_to_pfn_remapped()Peter Xu
hva_to_pfn_remapped() calls fixup_user_fault(), which has already handled the retry gracefully. Even if "unlocked" is set to true, it means that we've got a VM_FAULT_RETRY inside fixup_user_fault(), however the page fault has already retried and we should have the pfn set correctly. No need to do that again. Signed-off-by: Peter Xu <peterx@redhat.com> Message-Id: <20200416155906.267462-1-peterx@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-05-13kvm/eventfd: remove unneeded conversion to boolJason Yan
The '==' expression itself is bool, no need to convert it to bool again. This fixes the following coccicheck warning: virt/kvm/eventfd.c:724:38-43: WARNING: conversion to bool not needed here Signed-off-by: Jason Yan <yanaijie@huawei.com> Message-Id: <20200420123805.4494-1-yanaijie@huawei.com> Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-05-13kvm: Replace vcpu->swait with rcuwaitDavidlohr Bueso
The use of any sort of waitqueue (simple or regular) for wait/waking vcpus has always been an overkill and semantically wrong. Because this is per-vcpu (which is blocked) there is only ever a single waiting vcpu, thus no need for any sort of queue. As such, make use of the rcuwait primitive, with the following considerations: - rcuwait already provides the proper barriers that serialize concurrent waiter and waker. - Task wakeup is done in rcu read critical region, with a stable task pointer. - Because there is no concurrency among waiters, we need not worry about rcuwait_wait_event() calls corrupting the wait->task. As a consequence, this saves the locking done in swait when modifying the queue. This also applies to per-vcore wait for powerpc kvm-hv. The x86 tscdeadline_latency test mentioned in 8577370fb0cb ("KVM: Use simple waitqueue for vcpu->wq") shows that, on avg, latency is reduced by around 15-20% with this change. Cc: Paul Mackerras <paulus@ozlabs.org> Cc: kvmarm@lists.cs.columbia.edu Cc: linux-mips@vger.kernel.org Reviewed-by: Marc Zyngier <maz@kernel.org> Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Message-Id: <20200424054837.5138-6-dave@stgolabs.net> [Avoid extra logic changes. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-05-13Merge branch 'kvm-amd-fixes' into HEADPaolo Bonzini
2020-05-08KVM: Introduce kvm_make_all_cpus_request_except()Suravee Suthikulpanit
This allows making request to all other vcpus except the one specified in the parameter. Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com> Message-Id: <1588771076-73790-2-git-send-email-suravee.suthikulpanit@amd.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-05-01KVM: arm64: Fix 32bit PC wrap-aroundMarc Zyngier
In the unlikely event that a 32bit vcpu traps into the hypervisor on an instruction that is located right at the end of the 32bit range, the emulation of that instruction is going to increment PC past the 32bit range. This isn't great, as userspace can then observe this value and get a bit confused. Conversly, userspace can do things like (in the context of a 64bit guest that is capable of 32bit EL0) setting PSTATE to AArch64-EL0, set PC to a 64bit value, change PSTATE to AArch32-USR, and observe that PC hasn't been truncated. More confusion. Fix both by: - truncating PC increments for 32bit guests - sanitizing all 32bit regs every time a core reg is changed by userspace, and that PSTATE indicates a 32bit mode. Cc: stable@vger.kernel.org Acked-by: Will Deacon <will@kernel.org> Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-04-30KVM: arm64: vgic-v4: Initialize GICv4.1 even in the absence of a virtual ITSMarc Zyngier
KVM now expects to be able to use HW-accelerated delivery of vSGIs as soon as the guest has enabled thm. Unfortunately, we only initialize the GICv4 context if we have a virtual ITS exposed to the guest. Fix it by always initializing the GICv4.1 context if it is available on the host. Fixes: 2291ff2f2a56 ("KVM: arm64: GICv4.1: Plumb SGI implementation selection in the distributor") Reviewed-by: Zenghui Yu <yuzenghui@huawei.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-04-24kvm: add capability for halt pollingDavid Matlack
KVM_CAP_HALT_POLL is a per-VM capability that lets userspace control the halt-polling time, allowing halt-polling to be tuned or disabled on particular VMs. With dynamic halt-polling, a VM's VCPUs can poll from anywhere from [0, halt_poll_ns] on each halt. KVM_CAP_HALT_POLL sets the upper limit on the poll time. Signed-off-by: David Matlack <dmatlack@google.com> Signed-off-by: Jon Cargille <jcargill@google.com> Reviewed-by: Jim Mattson <jmattson@google.com> Message-Id: <20200417221446.108733-1-jcargill@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-04-23Merge branch 'kvm-arm64/vgic-fixes-5.7' into kvmarm-master/masterMarc Zyngier
2020-04-23KVM: arm64: vgic-its: Fix memory leak on the error path of vgic_add_lpi()Zenghui Yu
If we're going to fail out the vgic_add_lpi(), let's make sure the allocated vgic_irq memory is also freed. Though it seems that both cases are unlikely to fail. Signed-off-by: Zenghui Yu <yuzenghui@huawei.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20200414030349.625-3-yuzenghui@huawei.com
2020-04-23KVM: arm64: vgic-v3: Retire all pending LPIs on vcpu destroyZenghui Yu
It's likely that the vcpu fails to handle all virtual interrupts if userspace decides to destroy it, leaving the pending ones stay in the ap_list. If the un-handled one is a LPI, its vgic_irq structure will be eventually leaked because of an extra refcount increment in vgic_queue_irq_unlock(). This was detected by kmemleak on almost every guest destroy, the backtrace is as follows: unreferenced object 0xffff80725aed5500 (size 128): comm "CPU 5/KVM", pid 40711, jiffies 4298024754 (age 166366.512s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 08 01 a9 73 6d 80 ff ff ...........sm... c8 61 ee a9 00 20 ff ff 28 1e 55 81 6c 80 ff ff .a... ..(.U.l... backtrace: [<000000004bcaa122>] kmem_cache_alloc_trace+0x2dc/0x418 [<0000000069c7dabb>] vgic_add_lpi+0x88/0x418 [<00000000bfefd5c5>] vgic_its_cmd_handle_mapi+0x4dc/0x588 [<00000000cf993975>] vgic_its_process_commands.part.5+0x484/0x1198 [<000000004bd3f8e3>] vgic_its_process_commands+0x50/0x80 [<00000000b9a65b2b>] vgic_mmio_write_its_cwriter+0xac/0x108 [<0000000009641ebb>] dispatch_mmio_write+0xd0/0x188 [<000000008f79d288>] __kvm_io_bus_write+0x134/0x240 [<00000000882f39ac>] kvm_io_bus_write+0xe0/0x150 [<0000000078197602>] io_mem_abort+0x484/0x7b8 [<0000000060954e3c>] kvm_handle_guest_abort+0x4cc/0xa58 [<00000000e0d0cd65>] handle_exit+0x24c/0x770 [<00000000b44a7fad>] kvm_arch_vcpu_ioctl_run+0x460/0x1988 [<0000000025fb897c>] kvm_vcpu_ioctl+0x4f8/0xee0 [<000000003271e317>] do_vfs_ioctl+0x160/0xcd8 [<00000000e7f39607>] ksys_ioctl+0x98/0xd8 Fix it by retiring all pending LPIs in the ap_list on the destroy path. p.s. I can also reproduce it on a normal guest shutdown. It is because userspace still send LPIs to vcpu (through KVM_SIGNAL_MSI ioctl) while the guest is being shutdown and unable to handle it. A little strange though and haven't dig further... Reviewed-by: James Morse <james.morse@arm.com> Signed-off-by: Zenghui Yu <yuzenghui@huawei.com> [maz: moved the distributor deallocation down to avoid an UAF splat] Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20200414030349.625-2-yuzenghui@huawei.com
2020-04-23KVM: arm: vgic-v2: Only use the virtual state when userspace accesses ↵Marc Zyngier
pending bits There is no point in accessing the HW when writing to any of the ISPENDR/ICPENDR registers from userspace, as only the guest should be allowed to change the HW state. Introduce new userspace-specific accessors that deal solely with the virtual state. Note that the API differs from that of GICv3, where userspace exclusively uses ISPENDR to set the state. Too bad we can't reuse it. Fixes: 82e40f558de56 ("KVM: arm/arm64: vgic-v2: Handle SGI bits in GICD_I{S,C}PENDR0 as WI") Reviewed-by: James Morse <james.morse@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-04-22KVM: arm: vgic: Only use the virtual state when userspace accesses enable bitsMarc Zyngier
There is no point in accessing the HW when writing to any of the ISENABLER/ICENABLER registers from userspace, as only the guest should be allowed to change the HW state. Introduce new userspace-specific accessors that deal solely with the virtual state. Reported-by: James Morse <james.morse@arm.com> Tested-by: James Morse <james.morse@arm.com> Reviewed-by: James Morse <james.morse@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-04-22KVM: arm: vgic: Synchronize the whole guest on GIC{D,R}_I{S,C}ACTIVER readMarc Zyngier
When a guest tries to read the active state of its interrupts, we currently just return whatever state we have in memory. This means that if such an interrupt lives in a List Register on another CPU, we fail to obsertve the latest active state for this interrupt. In order to remedy this, stop all the other vcpus so that they exit and we can observe the most recent value for the state. This is similar to what we are doing for the write side of the same registers, and results in new MMIO handlers for userspace (which do not need to stop the guest, as it is supposed to be stopped already). Reported-by: Julien Grall <julien@xen.org> Reviewed-by: Andre Przywara <andre.przywara@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-04-21KVM: SVM: avoid infinite loop on NPF from bad addressPaolo Bonzini
When a nested page fault is taken from an address that does not have a memslot associated to it, kvm_mmu_do_page_fault returns RET_PF_EMULATE (via mmu_set_spte) and kvm_mmu_page_fault then invokes svm_need_emulation_on_page_fault. The default answer there is to return false, but in this case this just causes the page fault to be retried ad libitum. Since this is not a fast path, and the only other case where it is taken is an erratum, just stick a kvm_vcpu_gfn_to_memslot check in there to detect the common case where the erratum is not happening. This fixes an infinite loop in the new set_memory_region_test. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-04-21KVM: Remove redundant argument to kvm_arch_vcpu_ioctl_runTianjia Zhang
In earlier versions of kvm, 'kvm_run' was an independent structure and was not included in the vcpu structure. At present, 'kvm_run' is already included in the vcpu structure, so the parameter 'kvm_run' is redundant. This patch simplifies the function definition, removes the extra 'kvm_run' parameter, and extracts it from the 'kvm_vcpu' structure if necessary. Signed-off-by: Tianjia Zhang <tianjia.zhang@linux.alibaba.com> Message-Id: <20200416051057.26526-1-tianjia.zhang@linux.alibaba.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-04-21KVM: x86/mmu: Avoid an extra memslot lookup in try_async_pf() for L2Paolo Bonzini
Create a new function kvm_is_visible_memslot() and use it from kvm_is_visible_gfn(); use the new function in try_async_pf() too, to avoid an extra memslot lookup. Opportunistically squish a multi-line comment into a single-line comment. Note, the end result, KVM_PFN_NOSLOT, is unchanged. Cc: Jim Mattson <jmattson@google.com> Cc: Rick Edgecombe <rick.p.edgecombe@intel.com> Suggested-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-04-21KVM: x86: move kvm_create_vcpu_debugfs after last failure pointPaolo Bonzini
The placement of kvm_create_vcpu_debugfs is more or less irrelevant, since it cannot fail and userspace should not care about the debugfs entries until it knows the vcpu has been created. Moving it after the last failure point removes the need to remove the directory when unwinding the creation. Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Message-Id: <20200331224222.393439-1-pbonzini@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-04-17KVM: arm64: PSCI: Forbid 64bit functions for 32bit guestsMarc Zyngier
Implementing (and even advertising) 64bit PSCI functions to 32bit guests is at least a bit odd, if not altogether violating the spec which says ("5.2.1 Register usage in arguments and return values"): "Adherence to the SMC Calling Conventions implies that any AArch32 caller of an SMC64 function will get a return code of 0xFFFFFFFF(int32). This matches the NOT_SUPPORTED error code used in PSCI" Tighten the implementation by pretending these functions are not there for 32bit guests. Reviewed-by: Christoffer Dall <christoffer.dall@arm.com> Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-04-17KVM: arm64: PSCI: Narrow input registers when using 32bit functionsMarc Zyngier
When a guest delibarately uses an SMC32 function number (which is allowed), we should make sure we drop the top 32bits from the input arguments, as they could legitimately be junk. Reported-by: Christoffer Dall <christoffer.dall@arm.com> Reviewed-by: Christoffer Dall <christoffer.dall@arm.com> Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-04-15KVM: remove redundant assignment to variable rColin Ian King
The variable r is being assigned with a value that is never read and it is being updated later with a new value. The initialization is redundant and can be removed. Addresses-Coverity: ("Unused value") Signed-off-by: Colin Ian King <colin.king@canonical.com> Message-Id: <20200410113526.13822-1-colin.king@canonical.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-04-15KVM: arm: vgic: Fix limit condition when writing to GICD_I[CS]ACTIVERMarc Zyngier
When deciding whether a guest has to be stopped we check whether this is a private interrupt or not. Unfortunately, there's an off-by-one bug here, and we fail to recognize a whole range of interrupts as being global (GICv2 SPIs 32-63). Fix the condition from > to be >=. Cc: stable@vger.kernel.org Fixes: abd7229626b93 ("KVM: arm/arm64: Simplify active_change_prepare and plug race") Reported-by: André Przywara <andre.przywara@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-03-31KVM: Pass kvm_init()'s opaque param to additional arch funcsSean Christopherson
Pass @opaque to kvm_arch_hardware_setup() and kvm_arch_check_processor_compat() to allow architecture specific code to reference @opaque without having to stash it away in a temporary global variable. This will enable x86 to separate its vendor specific callback ops, which are passed via @opaque, into "init" and "runtime" ops without having to stash away the "init" ops. No functional change intended. Reviewed-by: Cornelia Huck <cohuck@redhat.com> Tested-by: Cornelia Huck <cohuck@redhat.com> #s390 Acked-by: Marc Zyngier <maz@kernel.org> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Message-Id: <20200321202603.19355-2-sean.j.christopherson@intel.com> Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-31Merge tag 'kvmarm-5.7' of ↵Paolo Bonzini
git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD KVM/arm updates for Linux 5.7 - GICv4.1 support - 32bit host removal
2020-03-26KVM: Fix out of range accesses to memslotsSean Christopherson
Reset the LRU slot if it becomes invalid when deleting a memslot to fix an out-of-bounds/use-after-free access when searching through memslots. Explicitly check for there being no used slots in search_memslots(), and in the caller of s390's approximation variant. Fixes: 36947254e5f9 ("KVM: Dynamically size memslot array based on number of used slots") Reported-by: Qian Cai <cai@lca.pw> Cc: Peter Xu <peterx@redhat.com> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Message-Id: <20200320205546.2396-2-sean.j.christopherson@intel.com> Acked-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-24Merge branch 'kvm-arm64/gic-v4.1' into kvmarm-master/nextMarc Zyngier
Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-03-24KVM: arm64: GICv4.1: Expose HW-based SGIs in debugfsMarc Zyngier
The vgic-state debugfs file could do with showing the pending state of the HW-backed SGIs. Plug it into the low-level code. Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Zenghui Yu <yuzenghui@huawei.com> Reviewed-by: Eric Auger <eric.auger@redhat.com> Link: https://lore.kernel.org/r/20200304203330.4967-24-maz@kernel.org
2020-03-24KVM: arm64: GICv4.1: Reload VLPI configuration on distributor enable/disableMarc Zyngier
Each time a Group-enable bit gets flipped, the state of these bits needs to be forwarded to the hardware. This is a pretty heavy handed operation, requiring all vcpus to reload their GICv4 configuration. It is thus implemented as a new request type. These enable bits are programmed into the HW by setting the VGrp{0,1}En fields of GICR_VPENDBASER when the vPEs are made resident again. Of course, we only support Group-1 for now... Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Zenghui Yu <yuzenghui@huawei.com> Link: https://lore.kernel.org/r/20200304203330.4967-22-maz@kernel.org
2020-03-24KVM: arm64: GICv4.1: Plumb SGI implementation selection in the distributorMarc Zyngier
The GICv4.1 architecture gives the hypervisor the option to let the guest choose whether it wants the good old SGIs with an active state, or the new, HW-based ones that do not have one. For this, plumb the configuration of SGIs into the GICv3 MMIO handling, present the GICD_TYPER2.nASSGIcap to the guest, and handle the GICD_CTLR.nASSGIreq setting. In order to be able to deal with the restore of a guest, also apply the GICD_CTLR.nASSGIreq setting at first run so that we can move the restored SGIs to the HW if that's what the guest had selected in a previous life. Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Zenghui Yu <yuzenghui@huawei.com> Link: https://lore.kernel.org/r/20200304203330.4967-21-maz@kernel.org
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