- 17 Jun, 2021 4 commits
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Siddharth Chandrasekaran authored
As of now there are 7 parameters (and flags) that are used in various hyper-v hypercall handlers. There are 6 more input/output parameters passed from XMM registers which are to be added in an upcoming patch. To make passing arguments to the handlers more readable, capture all these parameters into a single structure. Cc: Alexander Graf <graf@amazon.com> Cc: Evgeny Iakovlev <eyakovl@amazon.de> Signed-off-by:
Siddharth Chandrasekaran <sidcha@amazon.de> Message-Id: <273f7ed510a1f6ba177e61b73a5c7bfbee4a4a87.1622019133.git.sidcha@amazon.de> Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com>
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Siddharth Chandrasekaran authored
Hyper-v XMM fast hypercalls use XMM registers to pass input/output parameters. To access these, hyperv.c can reuse some FPU register accessors defined in emulator.c. Move them to a common location so both can access them. While at it, reorder the parameters of these accessor methods to make them more readable. Cc: Alexander Graf <graf@amazon.com> Cc: Evgeny Iakovlev <eyakovl@amazon.de> Signed-off-by:
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Shaokun Zhang authored
Function 'is_nx_huge_page_enabled' is called only by kvm/mmu, so make it as inline fucntion and remove the unnecessary declaration. Cc: Ben Gardon <bgardon@google.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Sean Christopherson <seanjc@google.com> Suggested-by:
Sean Christopherson <seanjc@google.com> Signed-off-by:
Shaokun Zhang <zhangshaokun@hisilicon.com> Message-Id: <1622102271-63107-1-git-send-email-zhangshaokun@hisilicon.com> Signed-off-by:
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Fuad Tabba authored
KVM_CHECK_EXTENSION ioctl can return any negative value on error, and not necessarily -1. Change the assertion to reflect that. Signed-off-by:
Fuad Tabba <tabba@google.com> Message-Id: <20210615150443.1183365-1-tabba@google.com> Signed-off-by:
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- 11 Jun, 2021 3 commits
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Sean Christopherson authored
Calculate and check the full mmu_role when initializing the MMU context for the nested MMU, where "full" means the bits and pieces of the role that aren't handled by kvm_calc_mmu_role_common(). While the nested MMU isn't used for shadow paging, things like the number of levels in the guest's page tables are surprisingly important when walking the guest page tables. Failure to reinitialize the nested MMU context if L2's paging mode changes can result in unexpected and/or missed page faults, and likely other explosions. E.g. if an L1 vCPU is running both a 32-bit PAE L2 and a 64-bit L2, the "common" role calculation will yield the same role for both L2s. If the 64-bit L2 is run after the 32-bit PAE L2, L0 will fail to reinitialize the nested MMU context, ultimately resulting in a bad walk of L2's page tables as the MMU will still have a guest root_level of PT32E_ROOT_LEVEL. WARNING: CPU: 4 PID: 167334 at arch/x86/kvm/vmx/vmx.c:3075 ept_save_pdptrs+0x15/0xe0 [kvm_intel] Modules linked in: kvm_intel] CPU: 4 PID: 167334 Comm: CPU 3/KVM Not tainted 5.13.0-rc1-d849817d5673-reqs #185 Hardware name: ASUS Q87M-E/Q87M-E, BIOS 1102 03/03/2014 RIP: 0010:ept_save_pdptrs+0x15/0xe0 [kvm_intel] Code: <0f> 0b c3 f6 87 d8 02 00f RSP: 0018:ffffbba702dbba00 EFLAGS: 00010202 RAX: 0000000000000011 RBX: 0000000000000002 RCX: ffffffff810a2c08 RDX: ffff91d7bc30acc0 RSI: 0000000000000011 RDI: ffff91d7bc30a600 RBP: ffff91d7bc30a600 R08: 0000000000000010 R09: 0000000000000007 R10: 0000000000000000 R11: 0000000000000000 R12: ffff91d7bc30a600 R13: ffff91d7bc30acc0 R14: ffff91d67c123460 R15: 0000000115d7e005 FS: 00007fe8e9ffb700(0000) GS:ffff91d90fb00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 000000029f15a001 CR4: 00000000001726e0 Call Trace: kvm_pdptr_read+0x3a/0x40 [kvm] paging64_walk_addr_generic+0x327/0x6a0 [kvm] paging64_gva_to_gpa_nested+0x3f/0xb0 [kvm] kvm_fetch_guest_virt+0x4c/0xb0 [kvm] __do_insn_fetch_bytes+0x11a/0x1f0 [kvm] x86_decode_insn+0x787/0x1490 [kvm] x86_decode_emulated_instruction+0x58/0x1e0 [kvm] x86_emulate_instruction+0x122/0x4f0 [kvm] vmx_handle_exit+0x120/0x660 [kvm_intel] kvm_arch_vcpu_ioctl_run+0xe25/0x1cb0 [kvm] kvm_vcpu_ioctl+0x211/0x5a0 [kvm] __x64_sys_ioctl+0x83/0xb0 do_syscall_64+0x40/0xb0 entry_SYSCALL_64_after_hwframe+0x44/0xae Cc: Vitaly Kuznetsov <vkuznets@redhat.com> Cc: stable@vger.kernel.org Fixes: bf627a92 ("x86/kvm/mmu: check if MMU reconfiguration is needed in init_kvm_nested_mmu()") Signed-off-by:
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Wanpeng Li authored
Commit c9b8b07c (KVM: x86: Dynamically allocate per-vCPU emulation context) tries to allocate per-vCPU emulation context dynamically, however, the x86_emulator slab cache is still exiting after the kvm module is unload as below after destroying the VM and unloading the kvm module. grep x86_emulator /proc/slabinfo x86_emulator 36 36 2672 12 8 : tunables 0 0 0 : slabdata 3 3 0 This patch fixes this slab cache leak by destroying the x86_emulator slab cache when the kvm module is unloaded. Fixes: c9b8b07c (KVM: x86: Dynamically allocate per-vCPU emulation context) Cc: stable@vger.kernel.org Signed-off-by:
Wanpeng Li <wanpengli@tencent.com> Message-Id: <1623387573-5969-1-git-send-email-wanpengli@tencent.com> Signed-off-by:
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Alper Gun authored
Send SEV_CMD_DECOMMISSION command to PSP firmware if ASID binding fails. If a failure happens after a successful LAUNCH_START command, a decommission command should be executed. Otherwise, guest context will be unfreed inside the AMD SP. After the firmware will not have memory to allocate more SEV guest context, LAUNCH_START command will begin to fail with SEV_RET_RESOURCE_LIMIT error. The existing code calls decommission inside sev_unbind_asid, but it is not called if a failure happens before guest activation succeeds. If sev_bind_asid fails, decommission is never called. PSP firmware has a limit for the number of guests. If sev_asid_binding fails many times, PSP firmware will not have resources to create another guest context. Cc: stable@vger.kernel.org Fixes: 59414c98 ("KVM: SVM: Add support for KVM_SEV_LAUNCH_START command") Reported-by:
Peter Gonda <pgonda@google.com> Signed-off-by:
Alper Gun <alpergun@google.com> Reviewed-by:
Marc Orr <marcorr@google.com> Signed-off-by:
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- 10 Jun, 2021 4 commits
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Sean Christopherson authored
Immediately reset the MMU context when the vCPU's SMM flag is cleared so that the SMM flag in the MMU role is always synchronized with the vCPU's flag. If RSM fails (which isn't correctly emulated), KVM will bail without calling post_leave_smm() and leave the MMU in a bad state. The bad MMU role can lead to a NULL pointer dereference when grabbing a shadow page's rmap for a page fault as the initial lookups for the gfn will happen with the vCPU's SMM flag (=0), whereas the rmap lookup will use the shadow page's SMM flag, which comes from the MMU (=1). SMM has an entirely different set of memslots, and so the initial lookup can find a memslot (SMM=0) and then explode on the rmap memslot lookup (SMM=1). general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] CPU: 1 PID: 8410 Comm: syz-executor382 Not tainted 5.13.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__gfn_to_rmap arch/x86/kvm/mmu/mmu.c:935 [inline] RIP: 0010:gfn_to_rmap+0x2b0/0x4d0 arch/x86/kvm/mmu/mmu.c:947 Code: <42> 80 3c 20 00 74 08 4c 89 ff e8 f1 79 a9 00 4c 89 fb 4d 8b 37 44 RSP: 0018:ffffc90000ffef98 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff888015b9f414 RCX: ffff888019669c40 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000001 RBP: 0000000000000001 R08: ffffffff811d9cdb R09: ffffed10065a6002 R10: ffffed10065a6002 R11: 0000000000000000 R12: dffffc0000000000 R13: 0000000000000003 R14: 0000000000000001 R15: 0000000000000000 FS: 000000000124b300(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 0000000028e31000 CR4: 00000000001526e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: rmap_add arch/x86/kvm/mmu/mmu.c:965 [inline] mmu_set_spte+0x862/0xe60 arch/x86/kvm/mmu/mmu.c:2604 __direct_map arch/x86/kvm/mmu/mmu.c:2862 [inline] direct_page_fault+0x1f74/0x2b70 arch/x86/kvm/mmu/mmu.c:3769 kvm_mmu_do_page_fault arch/x86/kvm/mmu.h:124 [inline] kvm_mmu_page_fault+0x199/0x1440 arch/x86/kvm/mmu/mmu.c:5065 vmx_handle_exit+0x26/0x160 arch/x86/kvm/vmx/vmx.c:6122 vcpu_enter_guest+0x3bdd/0x9630 arch/x86/kvm/x86.c:9428 vcpu_run+0x416/0xc20 arch/x86/kvm/x86.c:9494 kvm_arch_vcpu_ioctl_run+0x4e8/0xa40 arch/x86/kvm/x86.c:9722 kvm_vcpu_ioctl+0x70f/0xbb0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3460 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:1069 [inline] __se_sys_ioctl+0xfb/0x170 fs/ioctl.c:1055 do_syscall_64+0x3f/0xb0 arch/x86/entry/common.c:47 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x440ce9 Cc: stable@vger.kernel.org Reported-by: syzbot+fb0b6a7e8713aeb0319c@syzkaller.appspotmail.com Fixes: 9ec19493 ("KVM: x86: clear SMM flags before loading state while leaving SMM") Signed-off-by:
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Gustavo A. R. Silva authored
In preparation to enable -Wimplicit-fallthrough for Clang, fix a couple of warnings by explicitly adding break statements instead of just letting the code fall through to the next case. Link: https://github.com/KSPP/linux/issues/115Signed-off-by:
Gustavo A. R. Silva <gustavoars@kernel.org> Message-Id: <20210528200756.GA39320@embeddedor> Signed-off-by:
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ChenXiaoSong authored
Fix kernel-doc warnings: arch/x86/kvm/svm/avic.c:233: warning: Function parameter or member 'activate' not described in 'avic_update_access_page' arch/x86/kvm/svm/avic.c:233: warning: Function parameter or member 'kvm' not described in 'avic_update_access_page' arch/x86/kvm/svm/avic.c:781: warning: Function parameter or member 'e' not described in 'get_pi_vcpu_info' arch/x86/kvm/svm/avic.c:781: warning: Function parameter or member 'kvm' not described in 'get_pi_vcpu_info' arch/x86/kvm/svm/avic.c:781: warning: Function parameter or member 'svm' not described in 'get_pi_vcpu_info' arch/x86/kvm/svm/avic.c:781: warning: Function parameter or member 'vcpu_info' not described in 'get_pi_vcpu_info' arch/x86/kvm/svm/avic.c:1009: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst Signed-off-by:
ChenXiaoSong <chenxiaosong2@huawei.com> Message-Id: <20210609122217.2967131-1-chenxiaosong2@huawei.com> Signed-off-by:
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Yanan Wang authored
Errors like below were produced from test_util.c when compiling the KVM selftests on my local platform. lib/test_util.c: In function 'vm_mem_backing_src_alias': lib/test_util.c:177:12: error: initializer element is not constant .flag = anon_flags, ^~~~~~~~~~ lib/test_util.c:177:12: note: (near initialization for 'aliases[0].flag') The reason is that we are using non-const expressions to initialize the static structure, which will probably trigger a compiling error/warning on stricter GCC versions. Fix it by converting the two const variables "anon_flags" and "anon_huge_flags" into more stable macros. Fixes: b3784bc2 ("KVM: selftests: refactor vm_mem_backing_src_type flags") Reported-by:Zenghui Yu <yuzenghui@huawei.com> Signed-off-by:
Yanan Wang <wangyanan55@huawei.com> Message-Id: <20210610085418.35544-1-wangyanan55@huawei.com> Signed-off-by:
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- 09 Jun, 2021 2 commits
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Jim Mattson authored
Per the SDM, "any access that touches bytes 4 through 15 of an APIC register may cause undefined behavior and must not be executed." Worse, such an access in kvm_lapic_reg_read can result in a leak of kernel stack contents. Prior to commit 01402cf8 ("kvm: LAPIC: write down valid APIC registers"), such an access was explicitly disallowed. Restore the guard that was removed in that commit. Fixes: 01402cf8 ("kvm: LAPIC: write down valid APIC registers") Signed-off-by:
Jim Mattson <jmattson@google.com> Reported-by:
syzbot <syzkaller@googlegroups.com> Message-Id: <20210602205224.3189316-1-jmattson@google.com> Signed-off-by:
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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:
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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:
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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:
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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 13 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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