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2019-01-31KVM: x86: Fix single-step debuggingAlexander Popov1-2/+1
commit 5cc244a20b86090c087073c124284381cdf47234 upstream. The single-step debugging of KVM guests on x86 is broken: if we run gdb 'stepi' command at the breakpoint when the guest interrupts are enabled, RIP always jumps to native_apic_mem_write(). Then other nasty effects follow. Long investigation showed that on Jun 7, 2017 the commit c8401dda2f0a00cd25c0 ("KVM: x86: fix singlestepping over syscall") introduced the kvm_run.debug corruption: kvm_vcpu_do_singlestep() can be called without X86_EFLAGS_TF set. Let's fix it. Please consider that for -stable. Signed-off-by: Alexander Popov <alex.popov@linux.com> Cc: stable@vger.kernel.org Fixes: c8401dda2f0a00cd25c0 ("KVM: x86: fix singlestepping over syscall") Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-01-17x86,kvm: move qemu/guest FPU switching out to vcpu_runRik van Riel1-21/+13
commit f775b13eedee2f7f3c6fdd4e90fb79090ce5d339 upstream. Currently, every time a VCPU is scheduled out, the host kernel will first save the guest FPU/xstate context, then load the qemu userspace FPU context, only to then immediately save the qemu userspace FPU context back to memory. When scheduling in a VCPU, the same extraneous FPU loads and saves are done. This could be avoided by moving from a model where the guest FPU is loaded and stored with preemption disabled, to a model where the qemu userspace FPU is swapped out for the guest FPU context for the duration of the KVM_RUN ioctl. This is done under the VCPU mutex, which is also taken when other tasks inspect the VCPU FPU context, so the code should already be safe for this change. That should come as no surprise, given that s390 already has this optimization. This can fix a bug where KVM calls get_user_pages while owning the FPU, and the file system ends up requesting the FPU again: [258270.527947] __warn+0xcb/0xf0 [258270.527948] warn_slowpath_null+0x1d/0x20 [258270.527951] kernel_fpu_disable+0x3f/0x50 [258270.527953] __kernel_fpu_begin+0x49/0x100 [258270.527955] kernel_fpu_begin+0xe/0x10 [258270.527958] crc32c_pcl_intel_update+0x84/0xb0 [258270.527961] crypto_shash_update+0x3f/0x110 [258270.527968] crc32c+0x63/0x8a [libcrc32c] [258270.527975] dm_bm_checksum+0x1b/0x20 [dm_persistent_data] [258270.527978] node_prepare_for_write+0x44/0x70 [dm_persistent_data] [258270.527985] dm_block_manager_write_callback+0x41/0x50 [dm_persistent_data] [258270.527988] submit_io+0x170/0x1b0 [dm_bufio] [258270.527992] __write_dirty_buffer+0x89/0x90 [dm_bufio] [258270.527994] __make_buffer_clean+0x4f/0x80 [dm_bufio] [258270.527996] __try_evict_buffer+0x42/0x60 [dm_bufio] [258270.527998] dm_bufio_shrink_scan+0xc0/0x130 [dm_bufio] [258270.528002] shrink_slab.part.40+0x1f5/0x420 [258270.528004] shrink_node+0x22c/0x320 [258270.528006] do_try_to_free_pages+0xf5/0x330 [258270.528008] try_to_free_pages+0xe9/0x190 [258270.528009] __alloc_pages_slowpath+0x40f/0xba0 [258270.528011] __alloc_pages_nodemask+0x209/0x260 [258270.528014] alloc_pages_vma+0x1f1/0x250 [258270.528017] do_huge_pmd_anonymous_page+0x123/0x660 [258270.528021] handle_mm_fault+0xfd3/0x1330 [258270.528025] __get_user_pages+0x113/0x640 [258270.528027] get_user_pages+0x4f/0x60 [258270.528063] __gfn_to_pfn_memslot+0x120/0x3f0 [kvm] [258270.528108] try_async_pf+0x66/0x230 [kvm] [258270.528135] tdp_page_fault+0x130/0x280 [kvm] [258270.528149] kvm_mmu_page_fault+0x60/0x120 [kvm] [258270.528158] handle_ept_violation+0x91/0x170 [kvm_intel] [258270.528162] vmx_handle_exit+0x1ca/0x1400 [kvm_intel] No performance changes were detected in quick ping-pong tests on my 4 socket system, which is expected since an FPU+xstate load is on the order of 0.1us, while ping-ponging between CPUs is on the order of 20us, and somewhat noisy. Cc: stable@vger.kernel.org Signed-off-by: Rik van Riel <riel@redhat.com> Suggested-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> [Fixed a bug where reset_vcpu called put_fpu without preceding load_fpu, which happened inside from KVM_CREATE_VCPU ioctl. - Radim] Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-12-29kvm: x86: Add AMD's EX_CFG to the list of ignored MSRsEduardo Habkost1-0/+2
commit 0e1b869fff60c81b510c2d00602d778f8f59dd9a upstream. Some guests OSes (including Windows 10) write to MSR 0xc001102c on some cases (possibly while trying to apply a CPU errata). Make KVM ignore reads and writes to that MSR, so the guest won't crash. The MSR is documented as "Execution Unit Configuration (EX_CFG)", at AMD's "BIOS and Kernel Developer's Guide (BKDG) for AMD Family 15h Models 00h-0Fh Processors". Cc: stable@vger.kernel.org Signed-off-by: Eduardo Habkost <ehabkost@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-12-05KVM: X86: Fix scan ioapic use-before-initializationWanpeng Li1-1/+2
commit e97f852fd4561e77721bb9a4e0ea9d98305b1e93 upstream. Reported by syzkaller: BUG: unable to handle kernel NULL pointer dereference at 00000000000001c8 PGD 80000003ec4da067 P4D 80000003ec4da067 PUD 3f7bfa067 PMD 0 Oops: 0000 [#1] PREEMPT SMP PTI CPU: 7 PID: 5059 Comm: debug Tainted: G OE 4.19.0-rc5 #16 RIP: 0010:__lock_acquire+0x1a6/0x1990 Call Trace: lock_acquire+0xdb/0x210 _raw_spin_lock+0x38/0x70 kvm_ioapic_scan_entry+0x3e/0x110 [kvm] vcpu_enter_guest+0x167e/0x1910 [kvm] kvm_arch_vcpu_ioctl_run+0x35c/0x610 [kvm] kvm_vcpu_ioctl+0x3e9/0x6d0 [kvm] do_vfs_ioctl+0xa5/0x690 ksys_ioctl+0x6d/0x80 __x64_sys_ioctl+0x1a/0x20 do_syscall_64+0x83/0x6e0 entry_SYSCALL_64_after_hwframe+0x49/0xbe The reason is that the testcase writes hyperv synic HV_X64_MSR_SINT6 msr and triggers scan ioapic logic to load synic vectors into EOI exit bitmap. However, irqchip is not initialized by this simple testcase, ioapic/apic objects should not be accessed. This can be triggered by the following program: #define _GNU_SOURCE #include <endian.h> #include <stdint.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <sys/syscall.h> #include <sys/types.h> #include <unistd.h> uint64_t r[3] = {0xffffffffffffffff, 0xffffffffffffffff, 0xffffffffffffffff}; int main(void) { syscall(__NR_mmap, 0x20000000, 0x1000000, 3, 0x32, -1, 0); long res = 0; memcpy((void*)0x20000040, "/dev/kvm", 9); res = syscall(__NR_openat, 0xffffffffffffff9c, 0x20000040, 0, 0); if (res != -1) r[0] = res; res = syscall(__NR_ioctl, r[0], 0xae01, 0); if (res != -1) r[1] = res; res = syscall(__NR_ioctl, r[1], 0xae41, 0); if (res != -1) r[2] = res; memcpy( (void*)0x20000080, "\x01\x00\x00\x00\x00\x5b\x61\xbb\x96\x00\x00\x40\x00\x00\x00\x00\x01\x00" "\x08\x00\x00\x00\x00\x00\x0b\x77\xd1\x78\x4d\xd8\x3a\xed\xb1\x5c\x2e\x43" "\xaa\x43\x39\xd6\xff\xf5\xf0\xa8\x98\xf2\x3e\x37\x29\x89\xde\x88\xc6\x33" "\xfc\x2a\xdb\xb7\xe1\x4c\xac\x28\x61\x7b\x9c\xa9\xbc\x0d\xa0\x63\xfe\xfe" "\xe8\x75\xde\xdd\x19\x38\xdc\x34\xf5\xec\x05\xfd\xeb\x5d\xed\x2e\xaf\x22" "\xfa\xab\xb7\xe4\x42\x67\xd0\xaf\x06\x1c\x6a\x35\x67\x10\x55\xcb", 106); syscall(__NR_ioctl, r[2], 0x4008ae89, 0x20000080); syscall(__NR_ioctl, r[2], 0xae80, 0); return 0; } This patch fixes it by bailing out scan ioapic if ioapic is not initialized in kernel. Reported-by: Wei Wu <ww9210@gmail.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: Wei Wu <ww9210@gmail.com> Signed-off-by: Wanpeng Li <wanpengli@tencent.com> Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-12-05KVM: x86: Fix kernel info-leak in KVM_HC_CLOCK_PAIRING hypercallLiran Alon1-0/+1
commit bcbfbd8ec21096027f1ee13ce6c185e8175166f6 upstream. kvm_pv_clock_pairing() allocates local var "struct kvm_clock_pairing clock_pairing" on stack and initializes all it's fields besides padding (clock_pairing.pad[]). Because clock_pairing var is written completely (including padding) to guest memory, failure to init struct padding results in kernel info-leak. Fix the issue by making sure to also init the padding with zeroes. Fixes: 55dd00a73a51 ("KVM: x86: add KVM_HC_CLOCK_PAIRING hypercall") Reported-by: syzbot+a8ef68d71211ba264f56@syzkaller.appspotmail.com Reviewed-by: Mark Kanda <mark.kanda@oracle.com> Signed-off-by: Liran Alon <liran.alon@oracle.com> Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-11-04kvm: x86: fix WARN due to uninitialized guest FPU statePeter Xu1-3/+3
commit 5663d8f9bbe4bf15488f7351efb61ea20fa6de06 upstream ------------[ cut here ]------------ Bad FPU state detected at kvm_put_guest_fpu+0xd8/0x2d0 [kvm], reinitializing FPU registers. WARNING: CPU: 1 PID: 4594 at arch/x86/mm/extable.c:103 ex_handler_fprestore+0x88/0x90 CPU: 1 PID: 4594 Comm: qemu-system-x86 Tainted: G B OE 4.15.0-rc2+ #10 RIP: 0010:ex_handler_fprestore+0x88/0x90 Call Trace: fixup_exception+0x4e/0x60 do_general_protection+0xff/0x270 general_protection+0x22/0x30 RIP: 0010:kvm_put_guest_fpu+0xd8/0x2d0 [kvm] RSP: 0018:ffff8803d5627810 EFLAGS: 00010246 kvm_vcpu_reset+0x3b4/0x3c0 [kvm] kvm_apic_accept_events+0x1c0/0x240 [kvm] kvm_arch_vcpu_ioctl_run+0x1658/0x2fb0 [kvm] kvm_vcpu_ioctl+0x479/0x880 [kvm] do_vfs_ioctl+0x142/0x9a0 SyS_ioctl+0x74/0x80 do_syscall_64+0x15f/0x600 where kvm_put_guest_fpu is called without a prior kvm_load_guest_fpu. To fix it, move kvm_load_guest_fpu to the very beginning of kvm_arch_vcpu_ioctl_run. Cc: stable@vger.kernel.org Fixes: f775b13eedee2f7f3c6fdd4e90fb79090ce5d339 Signed-off-by: Peter Xu <peterx@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2018-09-15x86: kvm: avoid unused variable warningArnd Bergmann1-3/+1
commit 7288bde1f9df6c1475675419bdd7725ce84dec56 upstream. Removing one of the two accesses of the maxphyaddr variable led to a harmless warning: arch/x86/kvm/x86.c: In function 'kvm_set_mmio_spte_mask': arch/x86/kvm/x86.c:6563:6: error: unused variable 'maxphyaddr' [-Werror=unused-variable] Removing the #ifdef seems to be the nicest workaround, as it makes the code look cleaner than adding another #ifdef. Fixes: 28a1f3ac1d0c ("kvm: x86: Set highest physical address bits in non-present/reserved SPTEs") Signed-off-by: Arnd Bergmann <arnd@arndb.de> Cc: stable@vger.kernel.org # L1TF Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-15kvm: x86: Set highest physical address bits in non-present/reserved SPTEsJunaid Shahid1-2/+6
commit 28a1f3ac1d0c8558ee4453d9634dad891a6e922e upstream. Always set the 5 upper-most supported physical address bits to 1 for SPTEs that are marked as non-present or reserved, to make them unusable for L1TF attacks from the guest. Currently, this just applies to MMIO SPTEs. (We do not need to mark PTEs that are completely 0 as physical page 0 is already reserved.) This allows mitigation of L1TF without disabling hyper-threading by using shadow paging mode instead of EPT. Signed-off-by: Junaid Shahid <junaids@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-08-15KVM: VMX: Tell the nested hypervisor to skip L1D flush on vmentryPaolo Bonzini1-1/+25
commit 5b76a3cff011df2dcb6186c965a2e4d809a05ad4 upstream When nested virtualization is in use, VMENTER operations from the nested hypervisor into the nested guest will always be processed by the bare metal hypervisor, and KVM's "conditional cache flushes" mode in particular does a flush on nested vmentry. Therefore, include the "skip L1D flush on vmentry" bit in KVM's suggested ARCH_CAPABILITIES setting. Add the relevant Documentation. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-08-15KVM: VMX: support MSR_IA32_ARCH_CAPABILITIES as a feature MSRPaolo Bonzini1-1/+3
commit cd28325249a1ca0d771557ce823e0308ad629f98 upstream This lets userspace read the MSR_IA32_ARCH_CAPABILITIES and check that all requested features are available on the host. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-08-15KVM: X86: Allow userspace to define the microcode versionWanpeng Li1-2/+9
commit 518e7b94817abed94becfe6a44f1ece0d4745afe upstream Linux (among the others) has checks to make sure that certain features aren't enabled on a certain family/model/stepping if the microcode version isn't greater than or equal to a known good version. By exposing the real microcode version, we're preventing buggy guests that don't check that they are running virtualized (i.e., they should trust the hypervisor) from disabling features that are effectively not buggy. Suggested-by: Filippo Sironi <sironi@amazon.de> Signed-off-by: Wanpeng Li <wanpengli@tencent.com> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Cc: Liran Alon <liran.alon@oracle.com> Cc: Nadav Amit <nadav.amit@gmail.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Tom Lendacky <thomas.lendacky@amd.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-08-15KVM: X86: Introduce kvm_get_msr_feature()Wanpeng Li1-3/+15
commit 66421c1ec340096b291af763ed5721314cdd9c5c upstream Introduce kvm_get_msr_feature() to handle the msrs which are supported by different vendors and sharing the same emulation logic. Signed-off-by: Wanpeng Li <wanpengli@tencent.com> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Cc: Liran Alon <liran.alon@oracle.com> Cc: Nadav Amit <nadav.amit@gmail.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Tom Lendacky <thomas.lendacky@amd.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-08-15KVM: SVM: Add MSR-based feature support for serializing LFENCETom Lendacky1-0/+1
commit d1d93fa90f1afa926cb060b7f78ab01a65705b4d upstream In order to determine if LFENCE is a serializing instruction on AMD processors, MSR 0xc0011029 (MSR_F10H_DECFG) must be read and the state of bit 1 checked. This patch will add support to allow a guest to properly make this determination. Add the MSR feature callback operation to svm.c and add MSR 0xc0011029 to the list of MSR-based features. If LFENCE is serializing, then the feature is supported, allowing the hypervisor to set the value of the MSR that guest will see. Support is also added to write (hypervisor only) and read the MSR value for the guest. A write by the guest will result in a #GP. A read by the guest will return the value as set by the host. In this way, the support to expose the feature to the guest is controlled by the hypervisor. Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-08-15KVM: x86: Add a framework for supporting MSR-based featuresTom Lendacky1-5/+70
commit 801e459a6f3a63af9d447e6249088c76ae16efc4 upstream Provide a new KVM capability that allows bits within MSRs to be recognized as features. Two new ioctls are added to the /dev/kvm ioctl routine to retrieve the list of these MSRs and then retrieve their values. A kvm_x86_ops callback is used to determine support for the listed MSR-based features. Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> [Tweaked documentation. - Radim] Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-08-15x86/KVM/VMX: Add L1D flush logicPaolo Bonzini1-0/+8
commit c595ceee45707f00f64f61c54fb64ef0cc0b4e85 upstream Add the logic for flushing L1D on VMENTER. The flush depends on the static key being enabled and the new l1tf_flush_l1d flag being set. The flags is set: - Always, if the flush module parameter is 'always' - Conditionally at: - Entry to vcpu_run(), i.e. after executing user space - From the sched_in notifier, i.e. when switching to a vCPU thread. - From vmexit handlers which are considered unsafe, i.e. where sensitive data can be brought into L1D: - The emulator, which could be a good target for other speculative execution-based threats, - The MMU, which can bring host page tables in the L1 cache. - External interrupts - Nested operations that require the MMU (see above). That is vmptrld, vmptrst, vmclear,vmwrite,vmread. - When handling invept,invvpid [ tglx: Split out from combo patch and reduced to a single flag ] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-06-20x86: Delay skip of emulated hypercall instructionMarian Rotariu1-8/+11
[ Upstream commit 6356ee0c9602004e0a3b4b2dad68ee2ee9385b17 ] The IP increment should be done after the hypercall emulation, after calling the various handlers. In this way, these handlers can accurately identify the the IP of the VMCALL if they need it. This patch keeps the same functionality for the Hyper-V handler which does not use the return code of the standard kvm_skip_emulated_instruction() call. Signed-off-by: Marian Rotariu <mrotariu@bitdefender.com> [Hyper-V hypercalls also need kvm_skip_emulated_instruction() - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-06-16kvm: x86: use correct privilege level for sgdt/sidt/fxsave/fxrstor accessPaolo Bonzini1-4/+14
commit 3c9fa24ca7c9c47605672916491f79e8ccacb9e6 upstream. The functions that were used in the emulation of fxrstor, fxsave, sgdt and sidt were originally meant for task switching, and as such they did not check privilege levels. This is very bad when the same functions are used in the emulation of unprivileged instructions. This is CVE-2018-10853. The obvious fix is to add a new argument to ops->read_std and ops->write_std, which decides whether the access is a "system" access or should use the processor's CPL. Fixes: 129a72a0d3c8 ("KVM: x86: Introduce segmented_write_std", 2017-01-12) Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-06-16KVM: x86: pass kvm_vcpu to kvm_read_guest_virt and kvm_write_guest_virt_systemPaolo Bonzini1-13/+26
commit ce14e868a54edeb2e30cb7a7b104a2fc4b9d76ca upstream. Int the next patch the emulator's .read_std and .write_std callbacks will grow another argument, which is not needed in kvm_read_guest_virt and kvm_write_guest_virt_system's callers. Since we have to make separate functions, let's give the currently existing names a nicer interface, too. Fixes: 129a72a0d3c8 ("KVM: x86: Introduce segmented_write_std", 2017-01-12) Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-06-16KVM: X86: Fix reserved bits check for MOV to CR3Wanpeng Li1-1/+1
commit a780a3ea628268b2ad0ed43d7f28d90db0ff18be upstream. MSB of CR3 is a reserved bit if the PCIDE bit is not set in CR4. It should be checked when PCIDE bit is not set, however commit 'd1cd3ce900441 ("KVM: MMU: check guest CR3 reserved bits based on its physical address width")' removes the bit 63 checking unconditionally. This patch fixes it by checking bit 63 of CR3 when PCIDE bit is not set in CR4. Fixes: d1cd3ce900441 (KVM: MMU: check guest CR3 reserved bits based on its physical address width) Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: Liran Alon <liran.alon@oracle.com> Cc: stable@vger.kernel.org Reviewed-by: Junaid Shahid <junaids@google.com> Signed-off-by: Wanpeng Li <wanpengli@tencent.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-05-30KVM: x86: Update cpuid properly when CR4.OSXAVE or CR4.PKE is changedWei Huang1-1/+4
commit c4d2188206bafa177ea58e9a25b952baa0bf7712 upstream. The CPUID bits of OSXSAVE (function=0x1) and OSPKE (func=0x7, leaf=0x0) allows user apps to detect if OS has set CR4.OSXSAVE or CR4.PKE. KVM is supposed to update these CPUID bits when CR4 is updated. Current KVM code doesn't handle some special cases when updates come from emulator. Here is one example: Step 1: guest boots Step 2: guest OS enables XSAVE ==> CR4.OSXSAVE=1 and CPUID.OSXSAVE=1 Step 3: guest hot reboot ==> QEMU reset CR4 to 0, but CPUID.OSXAVE==1 Step 4: guest os checks CPUID.OSXAVE, detects 1, then executes xgetbv Step 4 above will cause an #UD and guest crash because guest OS hasn't turned on OSXAVE yet. This patch solves the problem by comparing the the old_cr4 with cr4. If the related bits have been changed, kvm_update_cpuid() needs to be called. Signed-off-by: Wei Huang <wei@redhat.com> Reviewed-by: Bandan Das <bsd@redhat.com> Cc: stable@vger.kernel.org Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-05-22KVM: SVM: Implement VIRT_SPEC_CTRL support for SSBDTom Lendacky1-9/+4
commit bc226f07dcd3c9ef0b7f6236fe356ea4a9cb4769 upstream Expose the new virtualized architectural mechanism, VIRT_SSBD, for using speculative store bypass disable (SSBD) under SVM. This will allow guests to use SSBD on hardware that uses non-architectural mechanisms for enabling SSBD. [ tglx: Folded the migration fixup from Paolo Bonzini ] Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-04-26x86/kvm/vmx: do not use vm-exit instruction length for fast MMIO when ↵Vitaly Kuznetsov1-1/+2
running nested [ Upstream commit d391f1207067268261add0485f0f34503539c5b0 ] I was investigating an issue with seabios >= 1.10 which stopped working for nested KVM on Hyper-V. The problem appears to be in handle_ept_violation() function: when we do fast mmio we need to skip the instruction so we do kvm_skip_emulated_instruction(). This, however, depends on VM_EXIT_INSTRUCTION_LEN field being set correctly in VMCS. However, this is not the case. Intel's manual doesn't mandate VM_EXIT_INSTRUCTION_LEN to be set when EPT MISCONFIG occurs. While on real hardware it was observed to be set, some hypervisors follow the spec and don't set it; we end up advancing IP with some random value. I checked with Microsoft and they confirmed they don't fill VM_EXIT_INSTRUCTION_LEN on EPT MISCONFIG. Fix the issue by doing instruction skip through emulator when running nested. Fixes: 68c3b4d1676d870f0453c31d5a52e7e65c7448ae Suggested-by: Radim Krčmář <rkrcmar@redhat.com> Suggested-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-04-26kvm: x86: fix KVM_XEN_HVM_CONFIG ioctlPaolo Bonzini1-3/+4
[ Upstream commit 51776043afa415435c7e4636204fbe4f7edc4501 ] This ioctl is obsolete (it was used by Xenner as far as I know) but still let's not break it gratuitously... Its handler is copying directly into struct kvm. Go through a bounce buffer instead, with the added benefit that we can actually do something useful with the flags argument---the previous code was exiting with -EINVAL but still doing the copy. This technically is a userspace ABI breakage, but since no one should be using the ioctl, it's a good occasion to see if someone actually complains. Cc: kernel-hardening@lists.openwall.com Cc: Kees Cook <keescook@chromium.org> Cc: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-03-09KVM/x86: remove WARN_ON() for when vm_munmap() failsEric Biggers1-4/+2
commit 103c763c72dd2df3e8c91f2d7ec88f98ed391111 upstream. On x86, special KVM memslots such as the TSS region have anonymous memory mappings created on behalf of userspace, and these mappings are removed when the VM is destroyed. It is however possible for removing these mappings via vm_munmap() to fail. This can most easily happen if the thread receives SIGKILL while it's waiting to acquire ->mmap_sem. This triggers the 'WARN_ON(r < 0)' in __x86_set_memory_region(). syzkaller was able to hit this, using 'exit()' to send the SIGKILL. Note that while the vm_munmap() failure results in the mapping not being removed immediately, it is not leaked forever but rather will be freed when the process exits. It's not really possible to handle this failure properly, so almost every other caller of vm_munmap() doesn't check the return value. It's a limitation of having the kernel manage these mappings rather than userspace. So just remove the WARN_ON() so that users can't spam the kernel log with this warning. Fixes: f0d648bdf0a5 ("KVM: x86: map/unmap private slots in __x86_set_memory_region") Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Jack Wang <jinpu.wang@profitbricks.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-03-09KVM/x86: Fix wrong macro references of X86_CR0_PG_BIT and X86_CR4_PAE_BIT in ↵Tianyu Lan1-2/+2
kvm_valid_sregs() commit 37b95951c58fdf08dc10afa9d02066ed9f176fb5 upstream. kvm_valid_sregs() should use X86_CR0_PG and X86_CR4_PAE to check bit status rather than X86_CR0_PG_BIT and X86_CR4_PAE_BIT. This patch is to fix it. Fixes: f29810335965a(KVM/x86: Check input paging mode when cs.l is set) Reported-by: Jeremi Piotrowski <jeremi.piotrowski@gmail.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Jack Wang <jinpu.wang@profitbricks.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-03-09KVM: x86: fix vcpu initialization with userspace lapicRadim Krčmář1-1/+2
commit b7e31be385584afe7f073130e8e570d53c95f7fe upstream. Moving the code around broke this rare configuration. Use this opportunity to finally call lapic reset from vcpu reset. Reported-by: syzbot+fb7a33a4b6c35007a72b@syzkaller.appspotmail.com Suggested-by: Paolo Bonzini <pbonzini@redhat.com> Fixes: 0b2e9904c159 ("KVM: x86: move LAPIC initialization after VMCS creation") Cc: stable@vger.kernel.org Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-03-09KVM: x86: move LAPIC initialization after VMCS creationPaolo Bonzini1-0/+1
commit 0b2e9904c15963e715d33e5f3f1387f17d19333a upstream. The initial reset of the local APIC is performed before the VMCS has been created, but it tries to do a vmwrite: vmwrite error: reg 810 value 4a00 (err 18944) CPU: 54 PID: 38652 Comm: qemu-kvm Tainted: G W I 4.16.0-0.rc2.git0.1.fc28.x86_64 #1 Hardware name: Intel Corporation S2600CW/S2600CW, BIOS SE5C610.86B.01.01.0003.090520141303 09/05/2014 Call Trace: vmx_set_rvi [kvm_intel] vmx_hwapic_irr_update [kvm_intel] kvm_lapic_reset [kvm] kvm_create_lapic [kvm] kvm_arch_vcpu_init [kvm] kvm_vcpu_init [kvm] vmx_create_vcpu [kvm_intel] kvm_vm_ioctl [kvm] Move it later, after the VMCS has been created. Fixes: 4191db26b714 ("KVM: x86: Update APICv on APIC reset") Cc: stable@vger.kernel.org Cc: Liran Alon <liran.alon@oracle.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-02-25KVM: x86: fix escape of guest dr6 to the hostWanpeng Li1-0/+6
commit efdab992813fb2ed825745625b83c05032e9cda2 upstream. syzkaller reported: WARNING: CPU: 0 PID: 12927 at arch/x86/kernel/traps.c:780 do_debug+0x222/0x250 CPU: 0 PID: 12927 Comm: syz-executor Tainted: G OE 4.15.0-rc2+ #16 RIP: 0010:do_debug+0x222/0x250 Call Trace: <#DB> debug+0x3e/0x70 RIP: 0010:copy_user_enhanced_fast_string+0x10/0x20 </#DB> _copy_from_user+0x5b/0x90 SyS_timer_create+0x33/0x80 entry_SYSCALL_64_fastpath+0x23/0x9a The testcase sets a watchpoint (with perf_event_open) on a buffer that is passed to timer_create() as the struct sigevent argument. In timer_create(), copy_from_user()'s rep movsb triggers the BP. The testcase also sets the debug registers for the guest. However, KVM only restores host debug registers when the host has active watchpoints, which triggers a race condition when running the testcase with multiple threads. The guest's DR6.BS bit can escape to the host before another thread invokes timer_create(), and do_debug() complains. The fix is to respect do_debug()'s dr6 invariant when leaving KVM. Reported-by: Dmitry Vyukov <dvyukov@google.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: David Hildenbrand <david@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Reviewed-by: David Hildenbrand <david@redhat.com> Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-02-25KVM/x86: Check input paging mode when cs.l is setLan Tianyu1-0/+26
commit f29810335965ac1f7bcb501ee2af5f039f792416 upstream. Reported by syzkaller: WARNING: CPU: 0 PID: 27962 at arch/x86/kvm/emulate.c:5631 x86_emulate_insn+0x557/0x15f0 [kvm] Modules linked in: kvm_intel kvm [last unloaded: kvm] CPU: 0 PID: 27962 Comm: syz-executor Tainted: G B W 4.15.0-rc2-next-20171208+ #32 Hardware name: Intel Corporation S1200SP/S1200SP, BIOS S1200SP.86B.01.03.0006.040720161253 04/07/2016 RIP: 0010:x86_emulate_insn+0x557/0x15f0 [kvm] RSP: 0018:ffff8807234476d0 EFLAGS: 00010282 RAX: 0000000000000000 RBX: ffff88072d0237a0 RCX: ffffffffa0065c4d RDX: 1ffff100e5a046f9 RSI: 0000000000000003 RDI: ffff88072d0237c8 RBP: ffff880723447728 R08: ffff88072d020000 R09: ffffffffa008d240 R10: 0000000000000002 R11: ffffed00e7d87db3 R12: ffff88072d0237c8 R13: ffff88072d023870 R14: ffff88072d0238c2 R15: ffffffffa008d080 FS: 00007f8a68666700(0000) GS:ffff880802200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000002009506c CR3: 000000071fec4005 CR4: 00000000003626f0 Call Trace: x86_emulate_instruction+0x3bc/0xb70 [kvm] ? reexecute_instruction.part.162+0x130/0x130 [kvm] vmx_handle_exit+0x46d/0x14f0 [kvm_intel] ? trace_event_raw_event_kvm_entry+0xe7/0x150 [kvm] ? handle_vmfunc+0x2f0/0x2f0 [kvm_intel] ? wait_lapic_expire+0x25/0x270 [kvm] vcpu_enter_guest+0x720/0x1ef0 [kvm] ... When CS.L is set, vcpu should run in the 64 bit paging mode. Current kvm set_sregs function doesn't have such check when userspace inputs sreg values. This will lead unexpected behavior. This patch is to add checks for CS.L, EFER.LME, EFER.LMA and CR4.PAE when get SREG inputs from userspace in order to avoid unexpected behavior. Suggested-by: Paolo Bonzini <pbonzini@redhat.com> Reported-by: Dmitry Vyukov <dvyukov@google.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Jim Mattson <jmattson@google.com> Signed-off-by: Tianyu Lan <tianyu.lan@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-02-07KVM/VMX: Allow direct access to MSR_IA32_SPEC_CTRLKarimAllah Ahmed1-1/+1
commit d28b387fb74da95d69d2615732f50cceb38e9a4d [ Based on a patch from Ashok Raj <ashok.raj@intel.com> ] Add direct access to MSR_IA32_SPEC_CTRL for guests. This is needed for guests that will only mitigate Spectre V2 through IBRS+IBPB and will not be using a retpoline+IBPB based approach. To avoid the overhead of saving and restoring the MSR_IA32_SPEC_CTRL for guests that do not actually use the MSR, only start saving and restoring when a non-zero is written to it. No attempt is made to handle STIBP here, intentionally. Filtering STIBP may be added in a future patch, which may require trapping all writes if we don't want to pass it through directly to the guest. [dwmw2: Clean up CPUID bits, save/restore manually, handle reset] Signed-off-by: KarimAllah Ahmed <karahmed@amazon.de> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Darren Kenny <darren.kenny@oracle.com> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Reviewed-by: Jim Mattson <jmattson@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Jun Nakajima <jun.nakajima@intel.com> Cc: kvm@vger.kernel.org Cc: Dave Hansen <dave.hansen@intel.com> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Asit Mallick <asit.k.mallick@intel.com> Cc: Arjan Van De Ven <arjan.van.de.ven@intel.com> Cc: Greg KH <gregkh@linuxfoundation.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Ashok Raj <ashok.raj@intel.com> Link: https://lkml.kernel.org/r/1517522386-18410-5-git-send-email-karahmed@amazon.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-02-07KVM/VMX: Emulate MSR_IA32_ARCH_CAPABILITIESKarimAllah Ahmed1-0/+1
commit 28c1c9fabf48d6ad596273a11c46e0d0da3e14cd Intel processors use MSR_IA32_ARCH_CAPABILITIES MSR to indicate RDCL_NO (bit 0) and IBRS_ALL (bit 1). This is a read-only MSR. By default the contents will come directly from the hardware, but user-space can still override it. [dwmw2: The bit in kvm_cpuid_7_0_edx_x86_features can be unconditional] Signed-off-by: KarimAllah Ahmed <karahmed@amazon.de> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Darren Kenny <darren.kenny@oracle.com> Reviewed-by: Jim Mattson <jmattson@google.com> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Jun Nakajima <jun.nakajima@intel.com> Cc: kvm@vger.kernel.org Cc: Dave Hansen <dave.hansen@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Asit Mallick <asit.k.mallick@intel.com> Cc: Arjan Van De Ven <arjan.van.de.ven@intel.com> Cc: Greg KH <gregkh@linuxfoundation.org> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Ashok Raj <ashok.raj@intel.com> Link: https://lkml.kernel.org/r/1517522386-18410-4-git-send-email-karahmed@amazon.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-02-03KVM: Let KVM_SET_SIGNAL_MASK work as advertisedJan H. Schönherr1-5/+2
[ Upstream commit 20b7035c66bacc909ae3ffe92c1a1ea7db99fe4f ] KVM API says for the signal mask you set via KVM_SET_SIGNAL_MASK, that "any unblocked signal received [...] will cause KVM_RUN to return with -EINTR" and that "the signal will only be delivered if not blocked by the original signal mask". This, however, is only true, when the calling task has a signal handler registered for a signal. If not, signal evaluation is short-circuited for SIG_IGN and SIG_DFL, and the signal is either ignored without KVM_RUN returning or the whole process is terminated. Make KVM_SET_SIGNAL_MASK behave as advertised by utilizing logic similar to that in do_sigtimedwait() to avoid short-circuiting of signals. Signed-off-by: Jan H. Schönherr <jschoenh@amazon.de> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Sasha Levin <alexander.levin@verizon.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-02-03KVM: X86: Fix softlockup when get the current kvmclockWanpeng Li1-4/+7
[ Upstream commit e70b57a6ce4e8b92a56a615ae79bdb2bd66035e7 ] watchdog: BUG: soft lockup - CPU#6 stuck for 22s! [qemu-system-x86:10185] CPU: 6 PID: 10185 Comm: qemu-system-x86 Tainted: G OE 4.14.0-rc4+ #4 RIP: 0010:kvm_get_time_scale+0x4e/0xa0 [kvm] Call Trace: get_time_ref_counter+0x5a/0x80 [kvm] kvm_hv_process_stimers+0x120/0x5f0 [kvm] kvm_arch_vcpu_ioctl_run+0x4b4/0x1690 [kvm] kvm_vcpu_ioctl+0x33a/0x620 [kvm] do_vfs_ioctl+0xa1/0x5d0 SyS_ioctl+0x79/0x90 entry_SYSCALL_64_fastpath+0x1e/0xa9 This can be reproduced when running kvm-unit-tests/hyperv_stimer.flat and cpu-hotplug stress simultaneously. __this_cpu_read(cpu_tsc_khz) returns 0 (set in kvmclock_cpu_down_prep()) when the pCPU is unhotplug which results in kvm_get_time_scale() gets into an infinite loop. This patch fixes it by treating the unhotplug pCPU as not using master clock. Reviewed-by: Radim Krčmář <rkrcmar@redhat.com> Reviewed-by: David Hildenbrand <david@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Sasha Levin <alexander.levin@verizon.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-02-03KVM: x86: emulator: Return to user-mode on L1 CPL=0 emulation failureLiran Alon1-1/+1
[ Upstream commit 1f4dcb3b213235e642088709a1c54964d23365e9 ] On this case, handle_emulation_failure() fills kvm_run with internal-error information which it expects to be delivered to user-mode for further processing. However, the code reports a wrong return-value which makes KVM to never return to user-mode on this scenario. Fixes: 6d77dbfc88e3 ("KVM: inject #UD if instruction emulation fails and exit to userspace") Signed-off-by: Liran Alon <liran.alon@oracle.com> Reviewed-by: Nikita Leshenko <nikita.leshchenko@oracle.com> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Reviewed-by: Wanpeng Li <wanpeng.li@hotmail.com> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Sasha Levin <alexander.levin@verizon.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-17KVM: Fix stack-out-of-bounds read in write_mmioWanpeng Li1-4/+4
commit e39d200fa5bf5b94a0948db0dae44c1b73b84a56 upstream. Reported by syzkaller: BUG: KASAN: stack-out-of-bounds in write_mmio+0x11e/0x270 [kvm] Read of size 8 at addr ffff8803259df7f8 by task syz-executor/32298 CPU: 6 PID: 32298 Comm: syz-executor Tainted: G OE 4.15.0-rc2+ #18 Hardware name: LENOVO ThinkCentre M8500t-N000/SHARKBAY, BIOS FBKTC1AUS 02/16/2016 Call Trace: dump_stack+0xab/0xe1 print_address_description+0x6b/0x290 kasan_report+0x28a/0x370 write_mmio+0x11e/0x270 [kvm] emulator_read_write_onepage+0x311/0x600 [kvm] emulator_read_write+0xef/0x240 [kvm] emulator_fix_hypercall+0x105/0x150 [kvm] em_hypercall+0x2b/0x80 [kvm] x86_emulate_insn+0x2b1/0x1640 [kvm] x86_emulate_instruction+0x39a/0xb90 [kvm] handle_exception+0x1b4/0x4d0 [kvm_intel] vcpu_enter_guest+0x15a0/0x2640 [kvm] kvm_arch_vcpu_ioctl_run+0x549/0x7d0 [kvm] kvm_vcpu_ioctl+0x479/0x880 [kvm] do_vfs_ioctl+0x142/0x9a0 SyS_ioctl+0x74/0x80 entry_SYSCALL_64_fastpath+0x23/0x9a The path of patched vmmcall will patch 3 bytes opcode 0F 01 C1(vmcall) to the guest memory, however, write_mmio tracepoint always prints 8 bytes through *(u64 *)val since kvm splits the mmio access into 8 bytes. This leaks 5 bytes from the kernel stack (CVE-2017-17741). This patch fixes it by just accessing the bytes which we operate on. Before patch: syz-executor-5567 [007] .... 51370.561696: kvm_mmio: mmio write len 3 gpa 0x10 val 0x1ffff10077c1010f After patch: syz-executor-13416 [002] .... 51302.299573: kvm_mmio: mmio write len 3 gpa 0x10 val 0xc1010f Reported-by: Dmitry Vyukov <dvyukov@google.com> Reviewed-by: Darren Kenny <darren.kenny@oracle.com> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Tested-by: Marc Zyngier <marc.zyngier@arm.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-12-29KVM: X86: Fix load RFLAGS w/o the fixed bitWanpeng Li1-1/+1
commit d73235d17ba63b53dc0e1051dbc10a1f1be91b71 upstream. *** Guest State *** CR0: actual=0x0000000000000030, shadow=0x0000000060000010, gh_mask=fffffffffffffff7 CR4: actual=0x0000000000002050, shadow=0x0000000000000000, gh_mask=ffffffffffffe871 CR3 = 0x00000000fffbc000 RSP = 0x0000000000000000 RIP = 0x0000000000000000 RFLAGS=0x00000000 DR7 = 0x0000000000000400 ^^^^^^^^^^ The failed vmentry is triggered by the following testcase when ept=Y: #include <unistd.h> #include <sys/syscall.h> #include <string.h> #include <stdint.h> #include <linux/kvm.h> #include <fcntl.h> #include <sys/ioctl.h> long r[5]; int main() { r[2] = open("/dev/kvm", O_RDONLY); r[3] = ioctl(r[2], KVM_CREATE_VM, 0); r[4] = ioctl(r[3], KVM_CREATE_VCPU, 7); struct kvm_regs regs = { .rflags = 0, }; ioctl(r[4], KVM_SET_REGS, &regs); ioctl(r[4], KVM_RUN, 0); } X86 RFLAGS bit 1 is fixed set, userspace can simply clearing bit 1 of RFLAGS with KVM_SET_REGS ioctl which results in vmentry fails. This patch fixes it by oring X86_EFLAGS_FIXED during ioctl. Suggested-by: Jim Mattson <jmattson@google.com> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Quan Xu <quan.xu0@gmail.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: Jim Mattson <jmattson@google.com> Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-12-14KVM: x86: fix APIC page invalidationRadim Krčmář1-0/+14
commit b1394e745b9453dcb5b0671c205b770e87dedb87 upstream. Implementation of the unpinned APIC page didn't update the VMCS address cache when invalidation was done through range mmu notifiers. This became a problem when the page notifier was removed. Re-introduce the arch-specific helper and call it from ...range_start. Reported-by: Fabian Grünbichler <f.gruenbichler@proxmox.com> Fixes: 38b9917350cb ("kvm: vmx: Implement set_apic_access_page_addr") Fixes: 369ea8242c0f ("mm/rmap: update to new mmu_notifier semantic v2") Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Andrea Arcangeli <aarcange@redhat.com> Tested-by: Wanpeng Li <wanpeng.li@hotmail.com> Tested-by: Fabian Grünbichler <f.gruenbichler@proxmox.com> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-12-05KVM: x86: inject exceptions produced by x86_decode_insnPaolo Bonzini1-0/+2
commit 6ea6e84309ca7e0e850b3083e6b09344ee15c290 upstream. Sometimes, a processor might execute an instruction while another processor is updating the page tables for that instruction's code page, but before the TLB shootdown completes. The interesting case happens if the page is in the TLB. In general, the processor will succeed in executing the instruction and nothing bad happens. However, what if the instruction is an MMIO access? If *that* happens, KVM invokes the emulator, and the emulator gets the updated page tables. If the update side had marked the code page as non present, the page table walk then will fail and so will x86_decode_insn. Unfortunately, even though kvm_fetch_guest_virt is correctly returning X86EMUL_PROPAGATE_FAULT, x86_decode_insn's caller treats the failure as a fatal error if the instruction cannot simply be reexecuted (as is the case for MMIO). And this in fact happened sometimes when rebooting Windows 2012r2 guests. Just checking ctxt->have_exception and injecting the exception if true is enough to fix the case. Thanks to Eduardo Habkost for helping in the debugging of this issue. Reported-by: Yanan Fu <yfu@redhat.com> Cc: Eduardo Habkost <ehabkost@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-12-05KVM: x86: pvclock: Handle first-time write to pvclock-page contains random junkLiran Alon1-0/+3
commit 51c4b8bba674cfd2260d173602c4dac08e4c3a99 upstream. When guest passes KVM it's pvclock-page GPA via WRMSR to MSR_KVM_SYSTEM_TIME / MSR_KVM_SYSTEM_TIME_NEW, KVM don't initialize pvclock-page to some start-values. It just requests a clock-update which will happen before entering to guest. The clock-update logic will call kvm_setup_pvclock_page() to update the pvclock-page with info. However, kvm_setup_pvclock_page() *wrongly* assumes that the version-field is initialized to an even number. This is wrong because at first-time write, field could be any-value. Fix simply makes sure that if first-time version-field is odd, increment it once more to make it even and only then start standard logic. This follows same logic as done in other pvclock shared-pages (See kvm_write_wall_clock() and record_steal_time()). Signed-off-by: Liran Alon <liran.alon@oracle.com> Reviewed-by: Nikita Leshenko <nikita.leshchenko@oracle.com> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-09-26x86/fpu: Rename fpu__activate_curr() to fpu__initialize()Ingo Molnar1-1/+1
Rename this function to better express that it's all about initializing the FPU state of a task which goes hand in hand with the fpu::initialized field. Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Eric Biggers <ebiggers3@gmail.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Yu-cheng Yu <yu-cheng.yu@intel.com> Link: http://lkml.kernel.org/r/20170923130016.21448-33-mingo@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-14KVM: async_pf: Fix #DF due to inject "Page not Present" and "Page Ready" ↵Wanpeng Li1-9/+28
exceptions simultaneously qemu-system-x86-8600 [004] d..1 7205.687530: kvm_entry: vcpu 2 qemu-system-x86-8600 [004] .... 7205.687532: kvm_exit: reason EXCEPTION_NMI rip 0xffffffffa921297d info ffffeb2c0e44e018 80000b0e qemu-system-x86-8600 [004] .... 7205.687532: kvm_page_fault: address ffffeb2c0e44e018 error_code 0 qemu-system-x86-8600 [004] .... 7205.687620: kvm_try_async_get_page: gva = 0xffffeb2c0e44e018, gfn = 0x427e4e qemu-system-x86-8600 [004] .N.. 7205.687628: kvm_async_pf_not_present: token 0x8b002 gva 0xffffeb2c0e44e018 kworker/4:2-7814 [004] .... 7205.687655: kvm_async_pf_completed: gva 0xffffeb2c0e44e018 address 0x7fcc30c4e000 qemu-system-x86-8600 [004] .... 7205.687703: kvm_async_pf_ready: token 0x8b002 gva 0xffffeb2c0e44e018 qemu-system-x86-8600 [004] d..1 7205.687711: kvm_entry: vcpu 2 After running some memory intensive workload in guest, I catch the kworker which completes the GUP too quickly, and queues an "Page Ready" #PF exception after the "Page not Present" exception before the next vmentry as the above trace which will result in #DF injected to guest. This patch fixes it by clearing the queue for "Page not Present" if "Page Ready" occurs before the next vmentry since the GUP has already got the required page and shadow page table has already been fixed by "Page Ready" handler. Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com> Fixes: 7c90705bf2a3 ("KVM: Inject asynchronous page fault into a PV guest if page is swapped out.") [Changed indentation and added clearing of injected. - Radim] Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
2017-09-14KVM: X86: Don't block vCPU if there is pending exceptionWanpeng Li1-0/+3
Don't block vCPU if there is pending exception. Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
2017-09-13KVM: Add struct kvm_vcpu pointer parameter to get_enable_apicv()Suravee Suthikulpanit1-1/+1
Modify struct kvm_x86_ops.arch.apicv_active() to take struct kvm_vcpu pointer as parameter in preparation to subsequent changes. Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
2017-09-13KVM: x86: Fix immediate_exit handling for uninitialized APJan H. Schönherr1-0/+4
When user space sets kvm_run->immediate_exit, KVM is supposed to return quickly. However, when a vCPU is in KVM_MP_STATE_UNINITIALIZED, the value is not considered and the vCPU blocks. Fix that oversight. Fixes: 460df4c1fc7c008 ("KVM: race-free exit from KVM_RUN without POSIX signals") Signed-off-by: Jan H. Schönherr <jschoenh@amazon.de> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
2017-09-13KVM: x86: Fix handling of pending signal on uninitialized APJan H. Schönherr1-0/+5
KVM API says that KVM_RUN will return with -EINTR when a signal is pending. However, if a vCPU is in KVM_MP_STATE_UNINITIALIZED, then the return value is unconditionally -EAGAIN. Copy over some code from vcpu_run(), so that the case of a pending signal results in the expected return value. Signed-off-by: Jan H. Schönherr <jschoenh@amazon.de> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
2017-09-09Merge tag 'kvm-4.14-1' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds1-86/+127
Pull KVM updates from Radim Krčmář: "First batch of KVM changes for 4.14 Common: - improve heuristic for boosting preempted spinlocks by ignoring VCPUs in user mode ARM: - fix for decoding external abort types from guests - added support for migrating the active priority of interrupts when running a GICv2 guest on a GICv3 host - minor cleanup PPC: - expose storage keys to userspace - merge kvm-ppc-fixes with a fix that missed 4.13 because of vacations - fixes s390: - merge of kvm/master to avoid conflicts with additional sthyi fixes - wire up the no-dat enhancements in KVM - multiple epoch facility (z14 feature) - Configuration z/Architecture Mode - more sthyi fixes - gdb server range checking fix - small code cleanups x86: - emulate Hyper-V TSC frequency MSRs - add nested INVPCID - emulate EPTP switching VMFUNC - support Virtual GIF - support 5 level page tables - speedup nested VM exits by packing byte operations - speedup MMIO by using hardware provided physical address - a lot of fixes and cleanups, especially nested" * tag 'kvm-4.14-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (67 commits) KVM: arm/arm64: Support uaccess of GICC_APRn KVM: arm/arm64: Extract GICv3 max APRn index calculation KVM: arm/arm64: vITS: Drop its_ite->lpi field KVM: arm/arm64: vgic: constify seq_operations and file_operations KVM: arm/arm64: Fix guest external abort matching KVM: PPC: Book3S HV: Fix memory leak in kvm_vm_ioctl_get_htab_fd KVM: s390: vsie: cleanup mcck reinjection KVM: s390: use WARN_ON_ONCE only for checking KVM: s390: guestdbg: fix range check KVM: PPC: Book3S HV: Report storage key support to userspace KVM: PPC: Book3S HV: Fix case where HDEC is treated as 32-bit on POWER9 KVM: PPC: Book3S HV: Fix invalid use of register expression KVM: PPC: Book3S HV: Fix H_REGISTER_VPA VPA size validation KVM: PPC: Book3S HV: Fix setting of storage key in H_ENTER KVM: PPC: e500mc: Fix a NULL dereference KVM: PPC: e500: Fix some NULL dereferences on error KVM: PPC: Book3S HV: Protect updates to spapr_tce_tables list KVM: s390: we are always in czam mode KVM: s390: expose no-DAT to guest and migration support KVM: s390: sthyi: remove invalid guest write access ...
2017-09-08Merge branch 'kvm-ppc-fixes' of ↵Radim Krčmář1-3/+14
git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc This fix was intended for 4.13, but didn't get in because both maintainers were on vacation. Paul Mackerras: "It adds mutual exclusion between list_add_rcu and list_del_rcu calls on the kvm->arch.spapr_tce_tables list. Without this, userspace could potentially trigger corruption of the list and cause a host crash or worse."
2017-09-04Merge branch 'x86-mm-for-linus' of ↵Linus Torvalds1-1/+2
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 mm changes from Ingo Molnar: "PCID support, 5-level paging support, Secure Memory Encryption support The main changes in this cycle are support for three new, complex hardware features of x86 CPUs: - Add 5-level paging support, which is a new hardware feature on upcoming Intel CPUs allowing up to 128 PB of virtual address space and 4 PB of physical RAM space - a 512-fold increase over the old limits. (Supercomputers of the future forecasting hurricanes on an ever warming planet can certainly make good use of more RAM.) Many of the necessary changes went upstream in previous cycles, v4.14 is the first kernel that can enable 5-level paging. This feature is activated via CONFIG_X86_5LEVEL=y - disabled by default. (By Kirill A. Shutemov) - Add 'encrypted memory' support, which is a new hardware feature on upcoming AMD CPUs ('Secure Memory Encryption', SME) allowing system RAM to be encrypted and decrypted (mostly) transparently by the CPU, with a little help from the kernel to transition to/from encrypted RAM. Such RAM should be more secure against various attacks like RAM access via the memory bus and should make the radio signature of memory bus traffic harder to intercept (and decrypt) as well. This feature is activated via CONFIG_AMD_MEM_ENCRYPT=y - disabled by default. (By Tom Lendacky) - Enable PCID optimized TLB flushing on newer Intel CPUs: PCID is a hardware feature that attaches an address space tag to TLB entries and thus allows to skip TLB flushing in many cases, even if we switch mm's. (By Andy Lutomirski) All three of these features were in the works for a long time, and it's coincidence of the three independent development paths that they are all enabled in v4.14 at once" * 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (65 commits) x86/mm: Enable RCU based page table freeing (CONFIG_HAVE_RCU_TABLE_FREE=y) x86/mm: Use pr_cont() in dump_pagetable() x86/mm: Fix SME encryption stack ptr handling kvm/x86: Avoid clearing the C-bit in rsvd_bits() x86/CPU: Align CR3 defines x86/mm, mm/hwpoison: Clear PRESENT bit for kernel 1:1 mappings of poison pages acpi, x86/mm: Remove encryption mask from ACPI page protection type x86/mm, kexec: Fix memory corruption with SME on successive kexecs x86/mm/pkeys: Fix typo in Documentation/x86/protection-keys.txt x86/mm/dump_pagetables: Speed up page tables dump for CONFIG_KASAN=y x86/mm: Implement PCID based optimization: try to preserve old TLB entries using PCID x86: Enable 5-level paging support via CONFIG_X86_5LEVEL=y x86/mm: Allow userspace have mappings above 47-bit x86/mm: Prepare to expose larger address space to userspace x86/mpx: Do not allow MPX if we have mappings above 47-bit x86/mm: Rename tasksize_32bit/64bit to task_size_32bit/64bit() x86/xen: Redefine XEN_ELFNOTE_INIT_P2M using PUD_SIZE * PTRS_PER_PUD x86/mm/dump_pagetables: Fix printout of p4d level x86/mm/dump_pagetables: Generalize address normalization x86/boot: Fix memremap() related build failure ...
2017-09-01KVM: update to new mmu_notifier semantic v2Jérôme Glisse1-11/+0
Calls to mmu_notifier_invalidate_page() were replaced by calls to mmu_notifier_invalidate_range() and are now bracketed by calls to mmu_notifier_invalidate_range_start()/end() Remove now useless invalidate_page callback. Changed since v1 (Linus Torvalds) - remove now useless kvm_arch_mmu_notifier_invalidate_page() Signed-off-by: Jérôme Glisse <jglisse@redhat.com> Tested-by: Mike Galbraith <efault@gmx.de> Tested-by: Adam Borowski <kilobyte@angband.pl> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: kvm@vger.kernel.org Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-08-26Merge branch 'linus' into x86/mm to pick up fixes and to fix conflictsIngo Molnar1-10/+14
Conflicts: arch/x86/kernel/head64.c arch/x86/mm/mmap.c Signed-off-by: Ingo Molnar <mingo@kernel.org>
generated by cgit v1.2.3 (git 2.39.0) at 2025-09-19 05:23:44 +0300