- 09 Jun, 2021 1 commit
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Paolo Bonzini authored
array_index_nospec does not work for uint64_t on 32-bit builds. However, the size of a memory slot must be less than 20 bits wide on those system, since the memory slot must fit in the user address space. So just store it in an unsigned long. Signed-off-by:Paolo Bonzini <pbonzini@redhat.com>
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- 08 Jun, 2021 9 commits
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Paolo Bonzini authored
KVM's mechanism for accessing guest memory translates a guest physical address (gpa) to a host virtual address using the right-shifted gpa (also known as gfn) and a struct kvm_memory_slot. The translation is performed in __gfn_to_hva_memslot using the following formula: hva = slot->userspace_addr + (gfn - slot->base_gfn) * PAGE_SIZE It is expected that gfn falls within the boundaries of the guest's physical memory. However, a guest can access invalid physical addresses in such a way that the gfn is invalid. __gfn_to_hva_memslot is called from kvm_vcpu_gfn_to_hva_prot, which first retrieves a memslot through __gfn_to_memslot. While __gfn_to_memslot does check that the gfn falls within the boundaries of the guest's physical memory or not, a CPU can speculate the result of the check and continue execution speculatively using an illegal gfn. The speculation can result in calculating an out-of-bounds hva. If the resulting host virtual address is used to load another guest physical address, this is effectively a Spectre gadget consisting of two consecutive reads, the second of which is data dependent on the first. Right now it's not clear if there are any cases in which this is exploitable. One interesting case was reported by the original author of this patch, and involves visiting guest page tables on x86. Right now these are not vulnerable because the hva read goes through get_user(), which contains an LFENCE speculation barrier. However, there are patches in progress for x86 uaccess.h to mask kernel addresses instead of using LFENCE; once these land, a guest could use speculation to read from the VMM's ring 3 address space. Other architectures such as ARM already use the address masking method, and would be susceptible to this same kind of data-dependent access gadgets. Therefore, this patch proactively protects from these attacks by masking out-of-bounds gfns in __gfn_to_hva_memslot, which blocks speculation of invalid hvas. Sean Christopherson noted that this patch does not cover kvm_read_guest_offset_cached. This however is limited to a few bytes past the end of the cache, and therefore it is unlikely to be useful in the context of building a chain of data dependent accesses. Reported-by:Artemiy Margaritov <artemiy.margaritov@gmail.com> Co-developed-by:
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Lai Jiangshan authored
When using shadow paging, unload the guest MMU when emulating a guest TLB flush to ensure all roots are synchronized. From the guest's perspective, flushing the TLB ensures any and all modifications to its PTEs will be recognized by the CPU. Note, unloading the MMU is overkill, but is done to mirror KVM's existing handling of INVPCID(all) and ensure the bug is squashed. Future cleanup can be done to more precisely synchronize roots when servicing a guest TLB flush. If TDP is enabled, synchronizing the MMU is unnecessary even if nested TDP is in play, as a "legacy" TLB flush from L1 does not invalidate L1's TDP mappings. For EPT, an explicit INVEPT is required to invalidate guest-physical mappings; for NPT, guest mappings are always tagged with an ASID and thus can only be invalidated via the VMCB's ASID control. This bug has existed since the introduction of KVM_VCPU_FLUSH_TLB. It was only recently exposed after Linux guests stopped flushing the local CPU's TLB prior to flushing remote TLBs (see commit 4ce94eab, "x86/mm/tlb: Flush remote and local TLBs concurrently"), but is also visible in Windows 10 guests. Tested-by:
Maxim Levitsky <mlevitsk@redhat.com> Reviewed-by:
Lai Jiangshan <laijs@linux.alibaba.com> [sean: massaged comment and changelog] Message-Id: <20210531172256.2908-1-jiangshanlai@gmail.com> Signed-off-by:
Sean Christopherson <seanjc@google.com> Cc: stable@vger.kernel.org Signed-off-by:
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Sean Christopherson authored
Use the __string() machinery provided by the tracing subystem to make a copy of the string literals consumed by the "nested VM-Enter failed" tracepoint. A complete copy is necessary to ensure that the tracepoint can't outlive the data/memory it consumes and deference stale memory. Because the tracepoint itself is defined by kvm, if kvm-intel and/or kvm-amd are built as modules, the memory holding the string literals defined by the vendor modules will be freed when the module is unloaded, whereas the tracepoint and its data in the ring buffer will live until kvm is unloaded (or "indefinitely" if kvm is built-in). This bug has existed since the tracepoint was added, but was recently exposed by a new check in tracing to detect exactly this type of bug. fmt: '%s%s ' current_buffer: ' vmx_dirty_log_t-140127 [003] .... kvm_nested_vmenter_failed: ' WARNING: CPU: 3 PID: 140134 at kernel/trace/trace.c:3759 trace_check_vprintf+0x3be/0x3e0 CPU: 3 PID: 140134 Comm: less Not tainted 5.13.0-rc1-ce2e73ce600a-req #184 Hardware name: ASUS Q87M-E/Q87M-E, BIOS 1102 03/03/2014 RIP: 0010:trace_check_vprintf+0x3be/0x3e0 Code: <0f> 0b 44 8b 4c 24 1c e9 a9 fe ff ff c6 44 02 ff 00 49 8b 97 b0 20 RSP: 0018:ffffa895cc37bcb0 EFLAGS: 00010282 RAX: 0000000000000000 RBX: ffffa895cc37bd08 RCX: 0000000000000027 RDX: 0000000000000027 RSI: 00000000ffffdfff RDI: ffff9766cfad74f8 RBP: ffffffffc0a041d4 R08: ffff9766cfad74f0 R09: ffffa895cc37bad8 R10: 0000000000000001 R11: 0000000000000001 R12: ffffffffc0a041d4 R13: ffffffffc0f4dba8 R14: 0000000000000000 R15: ffff976409f2c000 FS: 00007f92fa200740(0000) GS:ffff9766cfac0000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000559bd11b0000 CR3: 000000019fbaa002 CR4: 00000000001726e0 Call Trace: trace_event_printf+0x5e/0x80 trace_raw_output_kvm_nested_vmenter_failed+0x3a/0x60 [kvm] print_trace_line+0x1dd/0x4e0 s_show+0x45/0x150 seq_read_iter+0x2d5/0x4c0 seq_read+0x106/0x150 vfs_read+0x98/0x180 ksys_read+0x5f/0xe0 do_syscall_64+0x40/0xb0 entry_SYSCALL_64_after_hwframe+0x44/0xae Cc: Steven Rostedt <rostedt@goodmis.org> Fixes: 380e0055 ("KVM: nVMX: trace nested VM-Enter failures detected by H/W") Signed-off-by:
Steven Rostedt (VMware) <rostedt@goodmis.org> Message-Id: <20210607175748.674002-1-seanjc@google.com>
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Zhenzhong Duan authored
Until commit 39fe2fc9 ("selftests: kvm: make allocation of extra memory take effect", 2021-05-27), parameter extra_mem_pages was used only to calculate the page table size for all the memory chunks, because real memory allocation happened with calls of vm_userspace_mem_region_add() after vm_create_default(). Commit 39fe2fc9 however changed the meaning of extra_mem_pages to the size of memory slot 0. This makes the memory allocation more flexible, but makes it harder to account for the number of pages needed for the page tables. For example, memslot_perf_test has a small amount of memory in slot 0 but a lot in other slots, and adding that memory twice (both in slot 0 and with later calls to vm_userspace_mem_region_add()) causes an error that was fixed in commit 000ac429 ("selftests: kvm: fix overlapping addresses in memslot_perf_test", 2021-05-29) Since both uses are sensible, add a new parameter slot0_mem_pages to vm_create_with_vcpus() and some comments to clarify the meaning of slot0_mem_pages and extra_mem_pages. With this change, memslot_perf_test can go back to passing the number of memory pages as extra_mem_pages. Signed-off-by:
Zhenzhong Duan <zhenzhong.duan@intel.com> Message-Id: <20210608233816.423958-4-zhenzhong.duan@intel.com> [Squashed in a single patch and rewrote the commit message. - Paolo] Signed-off-by:
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Christian Borntraeger authored
s390x can have up to 47bits of physical guest and 64bits of virtual address bits. Add a new address mode to avoid errors of testcases going beyond 47bits. Signed-off-by:
Christian Borntraeger <borntraeger@de.ibm.com> Message-Id: <20210608123954.10991-1-borntraeger@de.ibm.com> Fixes: ef4c9f4f ("KVM: selftests: Fix 32-bit truncation of vm_get_max_gfn()") Cc: stable@vger.kernel.org Reviewed-by:
David Matlack <dmatlack@google.com> Signed-off-by:
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Lai Jiangshan authored
In record_steal_time(), st->preempted is read twice, and trace_kvm_pv_tlb_flush() might output result inconsistent if kvm_vcpu_flush_tlb_guest() see a different st->preempted later. It is a very trivial problem and hardly has actual harm and can be avoided by reseting and reading st->preempted in atomic way via xchg(). Signed-off-by:
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Lai Jiangshan authored
When computing the access permissions of a shadow page, use the effective permissions of the walk up to that point, i.e. the logic AND of its parents' permissions. Two guest PxE entries that point at the same table gfn need to be shadowed with different shadow pages if their parents' permissions are different. KVM currently uses the effective permissions of the last non-leaf entry for all non-leaf entries. Because all non-leaf SPTEs have full ("uwx") permissions, and the effective permissions are recorded only in role.access and merged into the leaves, this can lead to incorrect reuse of a shadow page and eventually to a missing guest protection page fault. For example, here is a shared pagetable: pgd[] pud[] pmd[] virtual address pointers /->pmd1(u--)->pte1(uw-)->page1 <- ptr1 (u--) /->pud1(uw-)--->pmd2(uw-)->pte2(uw-)->page2 <- ptr2 (uw-) pgd-| (shared pmd[] as above) \->pud2(u--)--->pmd1(u--)->pte1(uw-)->page1 <- ptr3 (u--) \->pmd2(uw-)->pte2(uw-)->page2 <- ptr4 (u--) pud1 and pud2 point to the same pmd table, so: - ptr1 and ptr3 points to the same page. - ptr2 and ptr4 points to the same page. (pud1 and pud2 here are pud entries, while pmd1 and pmd2 here are pmd entries) - First, the guest reads from ptr1 first and KVM prepares a shadow page table with role.access=u--, from ptr1's pud1 and ptr1's pmd1. "u--" comes from the effective permissions of pgd, pud1 and pmd1, which are stored in pt->access. "u--" is used also to get the pagetable for pud1, instead of "uw-". - Then the guest writes to ptr2 and KVM reuses pud1 which is present. The hypervisor set up a shadow page for ptr2 with pt->access is "uw-" even though the pud1 pmd (because of the incorrect argument to kvm_mmu_get_page in the previous step) has role.access="u--". - Then the guest reads from ptr3. The hypervisor reuses pud1's shadow pmd for pud2, because both use "u--" for their permissions. Thus, the shadow pmd already includes entries for both pmd1 and pmd2. - At last, the guest writes to ptr4. This causes no vmexit or pagefault, because pud1's shadow page structures included an "uw-" page even though its role.access was "u--". Any kind of shared pagetable might have the similar problem when in virtual machine without TDP enabled if the permissions are different from different ancestors. In order to fix the problem, we change pt->access to be an array, and any access in it will not include permissions ANDed from child ptes. The test code is: https://lore.kernel.org/kvm/20210603050537.19605-1-jiangshanlai@gmail.com/ Remember to test it with TDP disabled. The problem had existed long before the commit 41074d07 ("KVM: MMU: Fix inherited permissions for emulated guest pte updates"), and it is hard to find which is the culprit. So there is no fixes tag here. Signed-off-by: -
Wanpeng Li authored
According to the SDM 10.5.4.1: A write of 0 to the initial-count register effectively stops the local APIC timer, in both one-shot and periodic mode. However, the lapic timer oneshot/periodic mode which is emulated by vmx-preemption timer doesn't stop by writing 0 to TMICT since vmx->hv_deadline_tsc is still programmed and the guest will receive the spurious timer interrupt later. This patch fixes it by also cancelling the vmx-preemption timer when writing 0 to the initial-count register. Reviewed-by:
Wanpeng Li <wanpengli@tencent.com> Message-Id: <1623050385-100988-1-git-send-email-wanpengli@tencent.com> Signed-off-by:
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Ashish Kalra authored
KVM: SVM: Fix SEV SEND_START session length & SEND_UPDATE_DATA query length after commit 238eca82 Commit 238eca82 ("KVM: SVM: Allocate SEV command structures on local stack") uses the local stack to allocate the structures used to communicate with the PSP, which were earlier being kzalloced. This breaks SEV live migration for computing the SEND_START session length and SEND_UPDATE_DATA query length as session_len and trans_len and hdr_len fields are not zeroed respectively for the above commands before issuing the SEV Firmware API call, hence the firmware returns incorrect session length and update data header or trans length. Also the SEV Firmware API returns SEV_RET_INVALID_LEN firmware error for these length query API calls, and the return value and the firmware error needs to be passed to the userspace as it is, so need to remove the return check in the KVM code. Signed-off-by:
Ashish Kalra <ashish.kalra@amd.com> Message-Id: <20210607061532.27459-1-Ashish.Kalra@amd.com> Fixes: 238eca82 ("KVM: SVM: Allocate SEV command structures on local stack") Signed-off-by:
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- 29 May, 2021 1 commit
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Paolo Bonzini authored
vm_create allocates memory and maps it close to GPA. This memory is separate from what is allocated in subsequent calls to vm_userspace_mem_region_add, so it is incorrect to pass the test memory size to vm_create_default. Just pass a small fixed amount of memory which can be used later for page table, otherwise GPAs are already allocated at MEM_GPA and the test aborts. Signed-off-by:
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- 28 May, 2021 4 commits
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Paolo Bonzini authored
Merge tag 'kvmarm-fixes-5.13-2' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD KVM/arm64 fixes for 5.13, take #2 - Another state update on exit to userspace fix - Prevent the creation of mixed 32/64 VMs
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Wanpeng Li authored
ctxt->ud is consumed only by x86_decode_insn(), we can kill it off by passing emulation_type to x86_decode_insn() and dropping ctxt->ud altogether. Tracking that info in ctxt for literally one call is silly. Suggested-by:
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Wanpeng Li authored
Reported by syzkaller: WARNING: CPU: 7 PID: 10526 at linux/arch/x86/kvm//x86.c:7621 x86_emulate_instruction+0x41b/0x510 [kvm] RIP: 0010:x86_emulate_instruction+0x41b/0x510 [kvm] Call Trace: kvm_mmu_page_fault+0x126/0x8f0 [kvm] vmx_handle_exit+0x11e/0x680 [kvm_intel] vcpu_enter_guest+0xd95/0x1b40 [kvm] kvm_arch_vcpu_ioctl_run+0x377/0x6a0 [kvm] kvm_vcpu_ioctl+0x389/0x630 [kvm] __x64_sys_ioctl+0x8e/0xd0 do_syscall_64+0x3c/0xb0 entry_SYSCALL_64_after_hwframe+0x44/0xae Commit 4a1e10d5 ("KVM: x86: handle hardware breakpoints during emulation()) adds hardware breakpoints check before emulation the instruction and parts of emulation context initialization, actually we don't have the EMULTYPE_NO_DECODE flag here and the emulation context will not be reused. Commit c8848cee ("KVM: x86: set ctxt->have_exception in x86_decode_insn()) triggers the warning because it catches the stale emulation context has #UD, however, it is not during instruction decoding which should result in EMULATION_FAILED. This patch fixes it by moving the second part emulation context initialization into init_emulate_ctxt() and before hardware breakpoints check. The ctxt->ud will be dropped by a follow-up patch. syzkaller source: https://syzkaller.appspot.com/x/repro.c?x=134683fdd00000 Reported-by: syzbot+71271244f206d17f6441@syzkaller.appspotmail.com Fixes: 4a1e10d5 (KVM: x86: handle hardware breakpoints during emulation) Signed-off-by:
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Yuan Yao authored
The kvm_get_linear_rip() handles x86/long mode cases well and has better readability, __kvm_set_rflags() also use the paired function kvm_is_linear_rip() to check the vcpu->arch.singlestep_rip set in kvm_arch_vcpu_ioctl_set_guest_debug(), so change the "CS.BASE + RIP" code in kvm_arch_vcpu_ioctl_set_guest_debug() and handle_exception_nmi() to this one. Signed-off-by:
Yuan Yao <yuan.yao@intel.com> Message-Id: <20210526063828.1173-1-yuan.yao@linux.intel.com> Reviewed-by:
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- 27 May, 2021 25 commits
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David Matlack authored
This comment was left over from a previous version of the patch that introduced wrprot_gfn_range, when skip_4k was passed in instead of min_level. Signed-off-by:
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Marcelo Tosatti authored
For VMX, when a vcpu enters HLT emulation, pi_post_block will: 1) Add vcpu to per-cpu list of blocked vcpus. 2) Program the posted-interrupt descriptor "notification vector" to POSTED_INTR_WAKEUP_VECTOR With interrupt remapping, an interrupt will set the PIR bit for the vector programmed for the device on the CPU, test-and-set the ON bit on the posted interrupt descriptor, and if the ON bit is clear generate an interrupt for the notification vector. This way, the target CPU wakes upon a device interrupt and wakes up the target vcpu. Problem is that pi_post_block only programs the notification vector if kvm_arch_has_assigned_device() is true. Its possible for the following to happen: 1) vcpu V HLTs on pcpu P, kvm_arch_has_assigned_device is false, notification vector is not programmed 2) device is assigned to VM 3) device interrupts vcpu V, sets ON bit (notification vector not programmed, so pcpu P remains in idle) 4) vcpu 0 IPIs vcpu V (in guest), but since pi descriptor ON bit is set, kvm_vcpu_kick is skipped 5) vcpu 0 busy spins on vcpu V's response for several seconds, until RCU watchdog NMIs all vCPUs. To fix this, use the start_assignment kvm_x86_ops callback to kick vcpus out of the halt loop, so the notification vector is properly reprogrammed to the wakeup vector. Reported-by:
Pei Zhang <pezhang@redhat.com> Signed-off-by:
Marcelo Tosatti <mtosatti@redhat.com> Message-Id: <20210526172014.GA29007@fuller.cnet> Signed-off-by:
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Marcelo Tosatti authored
KVM_REQ_UNBLOCK will be used to exit a vcpu from its inner vcpu halt emulation loop. Rename KVM_REQ_PENDING_TIMER to KVM_REQ_UNBLOCK, switch PowerPC to arch specific request bit. Signed-off-by:
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Marcelo Tosatti authored
Add a start_assignment hook to kvm_x86_ops, which is called when kvm_arch_start_assignment is done. The hook is required to update the wakeup vector of a sleeping vCPU when a device is assigned to the guest. Signed-off-by:
Peter Xu <peterx@redhat.com> Signed-off-by:
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Wanpeng Li authored
Let's treat lapic_timer_advance_ns automatic tuning logic as hypervisor overhead, move it before wait_lapic_expire instead of between wait_lapic_expire and the world switch, the wait duration should be calculated by the up-to-date guest_tsc after the overhead of automatic tuning logic. This patch reduces ~30+ cycles for kvm-unit-tests/tscdeadline-latency when testing busy waits. Signed-off-by:
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Paolo Bonzini authored
The test takes a long time with the current implementation of memslots, so cut the run time a bit. Signed-off-by: -
Joe Richey authored
Replace BIT() in KVM's UPAI header with _BITUL(). BIT() is not defined in the UAPI headers and its usage may cause userspace build errors. Fixes: fb04a1ed ("KVM: X86: Implement ring-based dirty memory tracking") Signed-off-by:
Joe Richey <joerichey@google.com> Message-Id: <20210521085849.37676-3-joerichey94@gmail.com> Signed-off-by:
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Axel Rasmussen authored
This lets us run the demand paging test on top of a shared hugetlbfs-backed area. The "shared" is key, as this allows us to exercise userfaultfd minor faults on hugetlbfs. Signed-off-by:
Axel Rasmussen <axelrasmussen@google.com> Message-Id: <20210519200339.829146-11-axelrasmussen@google.com> Reviewed-by:
Ben Gardon <bgardon@google.com> Signed-off-by:
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Axel Rasmussen authored
UFFD handling of MINOR faults is a new feature whose use case is to speed up demand paging (compared to MISSING faults). So, it's interesting to let this selftest exercise this new mode. Modify the demand paging test to have the option of using UFFD minor faults, as opposed to missing faults. Now, when turning on userfaultfd with '-u', the desired mode has to be specified ("MISSING" or "MINOR"). If we're in minor mode, before registering, prefault via the *alias*. This way, the guest will trigger minor faults, instead of missing faults, and we can UFFDIO_CONTINUE to resolve them. Modify the page fault handler function to use the right ioctl depending on the mode we're running in. In MINOR mode, use UFFDIO_CONTINUE. Signed-off-by: -
Axel Rasmussen authored
When a memory region is added with a src_type specifying that it should use some kind of shared memory, also create an alias mapping to the same underlying physical pages. And, add an API so tests can get access to these alias addresses. Basically, for a guest physical address, let us look up the analogous host *alias* address. In a future commit, we'll modify the demand paging test to take advantage of this to exercise UFFD minor faults. The idea is, we pre-fault the underlying pages *via the alias*. When the *guest* faults, it gets a "minor" fault (PTEs don't exist yet, but a page is already in the page cache). Then, the userfaultfd theads can handle the fault: they could potentially modify the underlying memory *via the alias* if they wanted to, and then they install the PTEs and let the guest carry on via a UFFDIO_CONTINUE ioctl. Reviewed-by:
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Axel Rasmussen authored
This lets us run the demand paging test on top of a shmem-backed area. In follow-up commits, we'll 1) leverage this new capability to create an alias mapping, and then 2) use the alias mapping to exercise UFFD minor faults. Signed-off-by:
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Axel Rasmussen authored
Each struct vm_mem_backing_src_alias has a flags field, which denotes the flags used to mmap() an area of that type. Previously, this field never included MAP_PRIVATE | MAP_ANONYMOUS, because vm_userspace_mem_region_add assumed that *all* types would always use those flags, and so it hardcoded them. In a follow-up commit, we'll add a new type: shmem. Areas of this type must not have MAP_PRIVATE | MAP_ANONYMOUS, and instead they must have MAP_SHARED. So, refactor things. Make it so that the flags field of struct vm_mem_backing_src_alias really is a complete set of flags, and don't add in any extras in vm_userspace_mem_region_add. This will let us easily tack on shmem. Signed-off-by:
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Axel Rasmussen authored
Add an argument which lets us specify a different backing memory type for the test. The default is just to use anonymous, matching existing behavior. This is in preparation for testing UFFD minor faults. For that, we'll need to use a new backing memory type which is setup with MAP_SHARED. Signed-off-by:
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Axel Rasmussen authored
This is a preparatory commit needed before we can use different kinds of backing pages for guest memory. Previously, we used perf_test_args.host_page_size, which is the host's native page size (commonly 4K). For VM_MEM_SRC_ANONYMOUS this turns out to be okay, but in a follow-up commit we want to allow using different kinds of backing memory. Take VM_MEM_SRC_ANONYMOUS_HUGETLB for example. Without this change, if we used that backing page type, when we issued a UFFDIO_COPY ioctl we'd only do so with 4K, rather than the full 2M of a backing hugepage. In this case, UFFDIO_COPY returns -EINVAL (__mcopy_atomic_hugetlb checks the size). Signed-off-by:
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Axel Rasmussen authored
A small cleanup. Our caller writes: r = setup_demand_paging(...); if (r < 0) exit(-r); Since we're just going to exit anyway, instead of returning an error we can just re-use TEST_ASSERT. This makes the caller simpler, as well as the function itself - no need to write our branches, etc. Signed-off-by:
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David Matlack authored
If a KVM selftest is run on a machine without /dev/kvm, it will exit silently. Make it easy to tell what's happening by printing an error message. Opportunistically consolidate all codepaths that open /dev/kvm into a single function so they all print the same message. This slightly changes the semantics of vm_is_unrestricted_guest() by changing a TEST_ASSERT() to exit(KSFT_SKIP). However vm_is_unrestricted_guest() is only called in one place (x86_64/mmio_warning_test.c) and that is to determine if the test should be skipped or not. Signed-off-by:
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Axel Rasmussen authored
Some trivial fixes I found while touching related code in this series, factored out into a separate commit for easier reviewing: - s/gor/got/ and add a newline in demand_paging_test.c - s/backing_src/src_type/ in a comment to be consistent with the real function signature in kvm_util.c Signed-off-by:
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David Matlack authored
If /dev/kvm is not available then hardware_disable_test will hang indefinitely because the child process exits before posting to the semaphore for which the parent is waiting. Fix this by making the parent periodically check if the child has exited. We have to be careful to forward the child's exit status to preserve a KSFT_SKIP status. I considered just checking for /dev/kvm before creating the child process, but there are so many other reasons why the child could exit early that it seemed better to handle that as general case. Tested: $ ./hardware_disable_test /dev/kvm not available, skipping test $ echo $? 4 $ modprobe kvm_intel $ ./hardware_disable_test $ echo $? 0 Signed-off-by:
Andrew Jones <drjones@redhat.com> Signed-off-by:
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David Matlack authored
Similar to CPUID.0DH.0H this entry depends on the vCPU's XCR0 register and IA32_XSS MSR. Since this test does not control for either before assigning the vCPU's CPUID, these entries will not necessarily match the supported CPUID exposed by KVM. This fixes get_cpuid_test on Cascade Lake CPUs. Suggested-by:
Jim Mattson <jmattson@google.com> Signed-off-by:
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David Matlack authored
vm_get_max_gfn() casts vm->max_gfn from a uint64_t to an unsigned int, which causes the upper 32-bits of the max_gfn to get truncated. Nobody noticed until now likely because vm_get_max_gfn() is only used as a mechanism to create a memslot in an unused region of the guest physical address space (the top), and the top of the 32-bit physical address space was always good enough. This fix reveals a bug in memslot_modification_stress_test which was trying to create a dummy memslot past the end of guest physical memory. Fix that by moving the dummy memslot lower. Fixes: 52200d0d ("KVM: selftests: Remove duplicate guest mode handling") Reviewed-by:
Venkatesh Srinivas <venkateshs@chromium.org> Signed-off-by:
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Maciej S. Szmigiero authored
This benchmark contains the following tests: * Map test, where the host unmaps guest memory while the guest writes to it (maps it). The test is designed in a way to make the unmap operation on the host take a negligible amount of time in comparison with the mapping operation in the guest. The test area is actually split in two: the first half is being mapped by the guest while the second half in being unmapped by the host. Then a guest <-> host sync happens and the areas are reversed. * Unmap test which is broadly similar to the above map test, but it is designed in an opposite way: to make the mapping operation in the guest take a negligible amount of time in comparison with the unmap operation on the host. This test is available in two variants: with per-page unmap operation or a chunked one (using 2 MiB chunk size). * Move active area test which involves moving the last (highest gfn) memslot a bit back and forth on the host while the guest is concurrently writing around the area being moved (including over the moved memslot). * Move inactive area test which is similar to the previous move active area test, but now guest writes all happen outside of the area being moved. * Read / write test in which the guest writes to the beginning of each page of the test area while the host writes to the middle of each such page. Then each side checks the values the other side has written. This particular test is not expected to give different results depending on particular memslots implementation, it is meant as a rough sanity check and to provide insight on the spread of test results expected. Each test performs its operation in a loop until a test period ends (this is 5 seconds by default, but it is configurable). Then the total count of loops done is divided by the actual elapsed time to give the test result. The tests have a configurable memslot cap with the "-s" test option, by default the system maximum is used. Each test is repeated a particular number of times (by default 20 times), the best result achieved is printed. The test memory area is divided equally between memslots, the reminder is added to the last memslot. The test area size does not depend on the number of memslots in use. The tests also measure the time that it took to add all these memslots. The best result from the tests that use the whole test area is printed after all the requested tests are done. In general, these tests are designed to use as much memory as possible (within reason) while still doing 100+ loops even on high memslot counts with the default test length. Increasing the test runtime makes it increasingly more likely that some event will happen on the system during the test run, which might lower the test result. Signed-off-by:
Maciej S. Szmigiero <maciej.szmigiero@oracle.com> Reviewed-by:
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Maciej S. Szmigiero authored
The KVM selftest framework was using a simple list for keeping track of the memslots currently in use. This resulted in lookups and adding a single memslot being O(n), the later due to linear scanning of the existing memslot set to check for the presence of any conflicting entries. Before this change, benchmarking high count of memslots was more or less impossible as pretty much all the benchmark time was spent in the selftest framework code. We can simply use a rbtree for keeping track of both of gfn and hva. We don't need an interval tree for hva here as we can't have overlapping memslots because we allocate a completely new memory chunk for each new memslot. Signed-off-by:
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Paolo Bonzini authored
vm_vaddr_alloc() sets up GVA to GPA mapping page by page; therefore, GPAs may not be continuous if same memslot is used for data and page table allocation. kvm_vm_elf_load() however expects a continuous range of HVAs (and thus GPAs) because it does not try to read file data page by page. Fix this mismatch by allocating memory in one step. Reported-by:
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Zhenzhong Duan authored
The extra memory pages is missed to be allocated during VM creating. perf_test_util and kvm_page_table_test use it to alloc extra memory currently. Fix it by adding extra_mem_pages to the total memory calculation before allocate. Signed-off-by:
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Wanpeng Li authored
WARNING: suspicious RCU usage 5.13.0-rc1 #4 Not tainted ----------------------------- ./include/linux/kvm_host.h:710 suspicious rcu_dereference_check() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 1 lock held by hyperv_clock/8318: #0: ffffb6b8cb05a7d8 (&hv->hv_lock){+.+.}-{3:3}, at: kvm_hv_invalidate_tsc_page+0x3e/0xa0 [kvm] stack backtrace: CPU: 3 PID: 8318 Comm: hyperv_clock Not tainted 5.13.0-rc1 #4 Call Trace: dump_stack+0x87/0xb7 lockdep_rcu_suspicious+0xce/0xf0 kvm_write_guest_page+0x1c1/0x1d0 [kvm] kvm_write_guest+0x50/0x90 [kvm] kvm_hv_invalidate_tsc_page+0x79/0xa0 [kvm] kvm_gen_update_masterclock+0x1d/0x110 [kvm] kvm_arch_vm_ioctl+0x2a7/0xc50 [kvm] kvm_vm_ioctl+0x123/0x11d0 [kvm] __x64_sys_ioctl+0x3ed/0x9d0 do_syscall_64+0x3d/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xae kvm_memslots() will be called by kvm_write_guest(), so we should take the srcu lock. Fixes: e880c6ea (KVM: x86: hyper-v: Prevent using not-yet-updated TSC page by secondary CPUs) Reviewed-by:Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by:
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