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2021-01-29x86/fpu/64: Don't FNINIT in kernel_fpu_begin()Andy Lutomirski1-0/+12
The remaining callers of kernel_fpu_begin() in 64-bit kernels don't use 387 instructions, so there's no need to sanitize the FPU state. Skip it to get most of the performance we lost back. Reported-by: Krzysztof Olędzki <ole@ans.pl> Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/57f8841ccbf9f3c25a23196c888f5f6ec5887577.1611205691.git.luto@kernel.org
2021-01-29x86/fpu: Make the EFI FPU calling convention explicitAndy Lutomirski2-6/+22
EFI uses kernel_fpu_begin() to conform to the UEFI calling convention. This specifically requires initializing FCW (FPU Control Word), whereas no sane 64-bit kernel code should use legacy 387 operations that reference FCW. This should allow to safely change the default semantics of kernel_fpu_begin() to stop initializing FCW on 64-bit kernels. [ bp: Massage commit message a little. ] Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/25d392fff64680e0f4bb8cf0b1003314dc29eafe.1611205691.git.luto@kernel.org
2021-01-24Merge branch 'akpm' (patches from Andrew)Linus Torvalds1-11/+9
Merge misc fixes from Andrew Morton: "18 patches. Subsystems affected by this patch series: mm (pagealloc, memcg, kasan, memory-failure, and highmem), ubsan, proc, and MAINTAINERS" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: MAINTAINERS: add a couple more files to the Clang/LLVM section proc_sysctl: fix oops caused by incorrect command parameters powerpc/mm/highmem: use __set_pte_at() for kmap_local() mips/mm/highmem: use set_pte() for kmap_local() mm/highmem: prepare for overriding set_pte_at() sparc/mm/highmem: flush cache and TLB mm: fix page reference leak in soft_offline_page() ubsan: disable unsigned-overflow check for i386 kasan, mm: fix resetting page_alloc tags for HW_TAGS kasan, mm: fix conflicts with init_on_alloc/free kasan: fix HW_TAGS boot parameters kasan: fix incorrect arguments passing in kasan_add_zero_shadow kasan: fix unaligned address is unhandled in kasan_remove_zero_shadow mm: fix numa stats for thp migration mm: memcg: fix memcg file_dirty numa stat mm: memcg/slab: optimize objcg stock draining mm: fix initialization of struct page for holes in memory layout x86/setup: don't remove E820_TYPE_RAM for pfn 0
2021-01-24Merge tag 'sched_urgent_for_v5.11_rc5' of ↵Linus Torvalds1-0/+19
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler fixes from Borislav Petkov: - Correct the marking of kthreads which are supposed to run on a specific, single CPU vs such which are affine to only one CPU, mark per-cpu workqueue threads as such and make sure that marking "survives" CPU hotplug. Fix CPU hotplug issues with such kthreads. - A fix to not push away tasks on CPUs coming online. - Have workqueue CPU hotplug code use cpu_possible_mask when breaking affinity on CPU offlining so that pending workers can finish on newly arrived onlined CPUs too. - Dump tasks which haven't vacated a CPU which is currently being unplugged. - Register a special scale invariance callback which gets called on resume from RAM to read out APERF/MPERF after resume and thus make the schedutil scaling governor more precise. * tag 'sched_urgent_for_v5.11_rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched: Relax the set_cpus_allowed_ptr() semantics sched: Fix CPU hotplug / tighten is_per_cpu_kthread() sched: Prepare to use balance_push in ttwu() workqueue: Restrict affinity change to rescuer workqueue: Tag bound workers with KTHREAD_IS_PER_CPU kthread: Extract KTHREAD_IS_PER_CPU sched: Don't run cpu-online with balance_push() enabled workqueue: Use cpu_possible_mask instead of cpu_active_mask to break affinity sched/core: Print out straggler tasks in sched_cpu_dying() x86: PM: Register syscore_ops for scale invariance
2021-01-24Merge tag 'x86_urgent_for_v5.11_rc5' of ↵Linus Torvalds11-25/+65
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 fixes from Borislav Petkov: - Add a new Intel model number for Alder Lake - Differentiate which aspects of the FPU state get saved/restored when the FPU is used in-kernel and fix a boot crash on K7 due to early MXCSR access before CR4.OSFXSR is even set. - A couple of noinstr annotation fixes - Correct die ID setting on AMD for users of topology information which need the correct die ID - A SEV-ES fix to handle string port IO to/from kernel memory properly * tag 'x86_urgent_for_v5.11_rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/cpu: Add another Alder Lake CPU to the Intel family x86/mmx: Use KFPU_387 for MMX string operations x86/fpu: Add kernel_fpu_begin_mask() to selectively initialize state x86/topology: Make __max_die_per_package available unconditionally x86: __always_inline __{rd,wr}msr() x86/mce: Remove explicit/superfluous tracing locking/lockdep: Avoid noinstr warning for DEBUG_LOCKDEP locking/lockdep: Cure noinstr fail x86/sev: Fix nonistr violation x86/entry: Fix noinstr fail x86/cpu/amd: Set __max_die_per_package on AMD x86/sev-es: Handle string port IO to kernel memory properly
2021-01-24x86/setup: don't remove E820_TYPE_RAM for pfn 0Mike Rapoport1-11/+9
Patch series "mm: fix initialization of struct page for holes in memory layout", v3. Commit 73a6e474cb37 ("mm: memmap_init: iterate over memblock regions rather that check each PFN") exposed several issues with the memory map initialization and these patches fix those issues. Initially there were crashes during compaction that Qian Cai reported back in April [1]. It seemed back then that the problem was fixed, but a few weeks ago Andrea Arcangeli hit the same bug [2] and there was an additional discussion at [3]. [1] https://lore.kernel.org/lkml/8C537EB7-85EE-4DCF-943E-3CC0ED0DF56D@lca.pw [2] https://lore.kernel.org/lkml/20201121194506.13464-1-aarcange@redhat.com [3] https://lore.kernel.org/mm-commits/20201206005401.qKuAVgOXr%akpm@linux-foundation.org This patch (of 2): The first 4Kb of memory is a BIOS owned area and to avoid its allocation for the kernel it was not listed in e820 tables as memory. As the result, pfn 0 was never recognised by the generic memory management and it is not a part of neither node 0 nor ZONE_DMA. If set_pfnblock_flags_mask() would be ever called for the pageblock corresponding to the first 2Mbytes of memory, having pfn 0 outside of ZONE_DMA would trigger VM_BUG_ON_PAGE(!zone_spans_pfn(page_zone(page), pfn), page); Along with reserving the first 4Kb in e820 tables, several first pages are reserved with memblock in several places during setup_arch(). These reservations are enough to ensure the kernel does not touch the BIOS area and it is not necessary to remove E820_TYPE_RAM for pfn 0. Remove the update of e820 table that changes the type of pfn 0 and move the comment describing why it was done to trim_low_memory_range() that reserves the beginning of the memory. Link: https://lkml.kernel.org/r/20210111194017.22696-2-rppt@kernel.org Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Cc: Baoquan He <bhe@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: David Hildenbrand <david@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Michal Hocko <mhocko@kernel.org> Cc: Qian Cai <cai@lca.pw> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-01-22x86/cpu: Add another Alder Lake CPU to the Intel familyGayatri Kammela1-0/+1
Add Alder Lake mobile CPU model number to Intel family. Signed-off-by: Gayatri Kammela <gayatri.kammela@intel.com> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20210121215004.11618-1-tony.luck@intel.com
2021-01-21x86/mmx: Use KFPU_387 for MMX string operationsAndy Lutomirski1-5/+15
The default kernel_fpu_begin() doesn't work on systems that support XMM but haven't yet enabled CR4.OSFXSR. This causes crashes when _mmx_memcpy() is called too early because LDMXCSR generates #UD when the aforementioned bit is clear. Fix it by using kernel_fpu_begin_mask(KFPU_387) explicitly. Fixes: 7ad816762f9b ("x86/fpu: Reset MXCSR to default in kernel_fpu_begin()") Reported-by: Krzysztof Mazur <krzysiek@podlesie.net> Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Tested-by: Krzysztof Piotr Olędzki <ole@ans.pl> Tested-by: Krzysztof Mazur <krzysiek@podlesie.net> Cc: <stable@vger.kernel.org> Link: https://lkml.kernel.org/r/e7bf21855fe99e5f3baa27446e32623358f69e8d.1611205691.git.luto@kernel.org
2021-01-21x86/fpu: Add kernel_fpu_begin_mask() to selectively initialize stateAndy Lutomirski2-6/+18
Currently, requesting kernel FPU access doesn't distinguish which parts of the extended ("FPU") state are needed. This is nice for simplicity, but there are a few cases in which it's suboptimal: - The vast majority of in-kernel FPU users want XMM/YMM/ZMM state but do not use legacy 387 state. These users want MXCSR initialized but don't care about the FPU control word. Skipping FNINIT would save time. (Empirically, FNINIT is several times slower than LDMXCSR.) - Code that wants MMX doesn't want or need MXCSR initialized. _mmx_memcpy(), for example, can run before CR4.OSFXSR gets set, and initializing MXCSR will fail because LDMXCSR generates an #UD when the aforementioned CR4 bit is not set. - Any future in-kernel users of XFD (eXtended Feature Disable)-capable dynamic states will need special handling. Add a more specific API that allows callers to specify exactly what they want. Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Tested-by: Krzysztof Piotr Olędzki <ole@ans.pl> Link: https://lkml.kernel.org/r/aff1cac8b8fc7ee900cf73e8f2369966621b053f.1611205691.git.luto@kernel.org
2021-01-20Merge tag 'for-linus-5.11-rc5-tag' of ↵Linus Torvalds1-0/+2
git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip Pull xen fix from Juergen Gross: "A fix for build failure showing up in some configurations" * tag 'for-linus-5.11-rc5-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: x86/xen: fix 'nopvspin' build error
2021-01-19Merge tag 'hyperv-fixes-signed-20210119' of ↵Linus Torvalds1-3/+26
git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux Pull hyperv fix from Wei Liu: "One patch from Dexuan to fix clockevent initialization" * tag 'hyperv-fixes-signed-20210119' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux: x86/hyperv: Initialize clockevents after LAPIC is initialized
2021-01-19x86: PM: Register syscore_ops for scale invarianceRafael J. Wysocki1-0/+19
On x86 scale invariace tends to be disabled during resume from suspend-to-RAM, because the MPERF or APERF MSR values are not as expected then due to updates taking place after the platform firmware has been invoked to complete the suspend transition. That, of course, is not desirable, especially if the schedutil scaling governor is in use, because the lack of scale invariance causes it to be less reliable. To counter that effect, modify init_freq_invariance() to register a syscore_ops object for scale invariance with the ->resume callback pointing to init_counter_refs() which will run on the CPU starting the resume transition (the other CPUs will be taken care of the "online" operations taking place later). Fixes: e2b0d619b400 ("x86, sched: check for counters overflow in frequency invariant accounting") Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Giovanni Gherdovich <ggherdovich@suse.cz> Link: https://lkml.kernel.org/r/1803209.Mvru99baaF@kreacher
2021-01-18x86/xen: fix 'nopvspin' build errorRandy Dunlap1-0/+2
Fix build error in x86/xen/ when PARAVIRT_SPINLOCKS is not enabled. Fixes this build error: ../arch/x86/xen/smp_hvm.c: In function ‘xen_hvm_smp_init’: ../arch/x86/xen/smp_hvm.c:77:3: error: ‘nopvspin’ undeclared (first use in this function) nopvspin = true; Fixes: 3d7746bea925 ("x86/xen: Fix xen_hvm_smp_init() when vector callback not available") Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Reviewed-by: Juergen Gross <jgross@suse.com> Cc: David Woodhouse <dwmw@amazon.co.uk> Cc: Juergen Gross <jgross@suse.com> Link: https://lore.kernel.org/r/20210115191123.27572-1-rdunlap@infradead.org Signed-off-by: Juergen Gross <jgross@suse.com>
2021-01-17x86/hyperv: Initialize clockevents after LAPIC is initializedDexuan Cui1-3/+26
With commit 4df4cb9e99f8, the Hyper-V direct-mode STIMER is actually initialized before LAPIC is initialized: see apic_intr_mode_init() x86_platform.apic_post_init() hyperv_init() hv_stimer_alloc() apic_bsp_setup() setup_local_APIC() setup_local_APIC() temporarily disables LAPIC, initializes it and re-eanble it. The direct-mode STIMER depends on LAPIC, and when it's registered, it can be programmed immediately and the timer can fire very soon: hv_stimer_init clockevents_config_and_register clockevents_register_device tick_check_new_device tick_setup_device tick_setup_periodic(), tick_setup_oneshot() clockevents_program_event When the timer fires in the hypervisor, if the LAPIC is in the disabled state, new versions of Hyper-V ignore the event and don't inject the timer interrupt into the VM, and hence the VM hangs when it boots. Note: when the VM starts/reboots, the LAPIC is pre-enabled by the firmware, so the window of LAPIC being temporarily disabled is pretty small, and the issue can only happen once out of 100~200 reboots for a 40-vCPU VM on one dev host, and on another host the issue doesn't reproduce after 2000 reboots. The issue is more noticeable for kdump/kexec, because the LAPIC is disabled by the first kernel, and stays disabled until the kdump/kexec kernel enables it. This is especially an issue to a Generation-2 VM (for which Hyper-V doesn't emulate the PIT timer) when CONFIG_HZ=1000 (rather than CONFIG_HZ=250) is used. Fix the issue by moving hv_stimer_alloc() to a later place where the LAPIC timer is initialized. Fixes: 4df4cb9e99f8 ("x86/hyperv: Initialize clockevents earlier in CPU onlining") Signed-off-by: Dexuan Cui <decui@microsoft.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Link: https://lore.kernel.org/r/20210116223136.13892-1-decui@microsoft.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-01-15Merge tag 'for-linus-5.11-rc4-tag' of ↵Linus Torvalds2-13/+29
git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip Pull xen fixes from Juergen Gross: - A series to fix a regression when running as a fully virtualized guest on an old Xen hypervisor not supporting PV interrupt callbacks for HVM guests. - A patch to add support to query Xen resource sizes (setting was possible already) from user mode. * tag 'for-linus-5.11-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: x86/xen: Fix xen_hvm_smp_init() when vector callback not available x86/xen: Don't register Xen IPIs when they aren't going to be used x86/xen: Add xen_no_vector_callback option to test PCI INTX delivery xen: Set platform PCI device INTX affinity to CPU0 xen: Fix event channel callback via INTX/GSI xen/privcmd: allow fetching resource sizes
2021-01-14x86/topology: Make __max_die_per_package available unconditionallyBorislav Petkov2-3/+3
Move it outside of CONFIG_SMP in order to avoid ifdeffery at the usage sites. Fixes: 76e2fc63ca40 ("x86/cpu/amd: Set __max_die_per_package on AMD") Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20210114111814.5346-1-bp@alien8.de
2021-01-13x86/xen: Fix xen_hvm_smp_init() when vector callback not availableDavid Woodhouse1-10/+17
Only the IPI-related functions in the smp_ops should be conditional on the vector callback being available. The rest should still happen: • xen_hvm_smp_prepare_boot_cpu() This function does two things, both of which should still happen if there is no vector callback support. The call to xen_vcpu_setup() for vCPU0 should still happen as it just sets up the vcpu_info for CPU0. That does happen for the secondary vCPUs too, from xen_cpu_up_prepare_hvm(). The second thing it does is call xen_init_spinlocks(), which perhaps counter-intuitively should *also* still be happening in the case without vector callbacks, so that it can clear its local xen_pvspin flag and disable the virt_spin_lock_key accordingly. Checking xen_have_vector_callback in xen_init_spinlocks() itself would affect PV guests, so set the global nopvspin flag in xen_hvm_smp_init() instead, when vector callbacks aren't available. • xen_hvm_smp_prepare_cpus() This does some IPI-related setup by calling xen_smp_intr_init() and xen_init_lock_cpu(), which can be made conditional. And it sets the xen_vcpu_id to XEN_VCPU_ID_INVALID for all possible CPUS, which does need to happen. • xen_smp_cpus_done() This offlines any vCPUs which doesn't fit in the global shared_info page, if separate vcpu_info placement isn't available. That part also needs to happen regardless of vector callback support. • xen_hvm_cpu_die() This doesn't actually do anything other than commin_cpu_die() right right now in the !vector_callback case; all three teardown functions it calls should be no-ops. But to guard against future regressions it's useful to call it anyway, and for it to explicitly check for xen_have_vector_callback before calling those additional functions. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Link: https://lore.kernel.org/r/20210106153958.584169-6-dwmw2@infradead.org Signed-off-by: Juergen Gross <jgross@suse.com>
2021-01-13x86/xen: Don't register Xen IPIs when they aren't going to be usedDavid Woodhouse1-2/+2
In the case where xen_have_vector_callback is false, we still register the IPI vectors in xen_smp_intr_init() for the secondary CPUs even though they aren't going to be used. Stop doing that. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Link: https://lore.kernel.org/r/20210106153958.584169-5-dwmw2@infradead.org Signed-off-by: Juergen Gross <jgross@suse.com>
2021-01-13x86/xen: Add xen_no_vector_callback option to test PCI INTX deliveryDavid Woodhouse1-1/+10
It's useful to be able to test non-vector event channel delivery, to make sure Linux will work properly on older Xen which doesn't have it. It's also useful for those working on Xen and Xen-compatible hypervisors, because there are guest kernels still in active use which use PCI INTX even when vector delivery is available. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Link: https://lore.kernel.org/r/20210106153958.584169-4-dwmw2@infradead.org Signed-off-by: Juergen Gross <jgross@suse.com>
2021-01-12x86: __always_inline __{rd,wr}msr()Peter Zijlstra1-2/+2
When the compiler choses to not inline the trivial MSR helpers: vmlinux.o: warning: objtool: __sev_es_nmi_complete()+0xce: call to __wrmsr.constprop.14() leaves .noinstr.text section Reported-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Randy Dunlap <rdunlap@infradead.org> # build-tested Link: https://lore.kernel.org/r/X/bf3gV+BW7kGEsB@hirez.programming.kicks-ass.net
2021-01-12x86/mce: Remove explicit/superfluous tracingPeter Zijlstra1-3/+4
There's some explicit tracing left in exc_machine_check_kernel(), remove it, as it's already implied by irqentry_nmi_enter(). Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20210106144017.719310466@infradead.org
2021-01-12x86/sev: Fix nonistr violationPeter Zijlstra1-1/+1
When the compiler fails to inline, it violates nonisntr: vmlinux.o: warning: objtool: __sev_es_nmi_complete()+0xc7: call to sev_es_wr_ghcb_msr() leaves .noinstr.text section Fixes: 4ca68e023b11 ("x86/sev-es: Handle NMI State") Reported-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20210106144017.532902065@infradead.org
2021-01-12x86/entry: Fix noinstr failPeter Zijlstra1-3/+7
vmlinux.o: warning: objtool: __do_fast_syscall_32()+0x47: call to syscall_enter_from_user_mode_work() leaves .noinstr.text section Fixes: 4facb95b7ada ("x86/entry: Unbreak 32bit fast syscall") Reported-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20210106144017.472696632@infradead.org
2021-01-12x86/cpu/amd: Set __max_die_per_package on AMDYazen Ghannam1-2/+2
Set the maximum DIE per package variable on AMD using the NodesPerProcessor topology value. This will be used by RAPL, among others, to determine the maximum number of DIEs on the system in order to do per-DIE manipulations. [ bp: Productize into a proper patch. ] Fixes: 028c221ed190 ("x86/CPU/AMD: Save AMD NodeId as cpu_die_id") Reported-by: Johnathan Smithinovic <johnathan.smithinovic@gmx.at> Reported-by: Rafael Kitover <rkitover@gmail.com> Signed-off-by: Yazen Ghannam <Yazen.Ghannam@amd.com> Signed-off-by: Borislav Petkov <bp@suse.de> Tested-by: Johnathan Smithinovic <johnathan.smithinovic@gmx.at> Tested-by: Rafael Kitover <rkitover@gmail.com> Link: https://bugzilla.kernel.org/show_bug.cgi?id=210939 Link: https://lkml.kernel.org/r/20210106112106.GE5729@zn.tnic Link: https://lkml.kernel.org/r/20210111101455.1194-1-bp@alien8.de
2021-01-11Merge tag 'hyperv-fixes-signed-20210111' of ↵Linus Torvalds4-3/+33
git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux Pull hyperv fixes from Wei Liu: - fix kexec panic/hang (Dexuan Cui) - fix occasional crashes when flushing TLB (Wei Liu) * tag 'hyperv-fixes-signed-20210111' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux: x86/hyperv: check cpu mask after interrupt has been disabled x86/hyperv: Fix kexec panic/hang issues
2021-01-11x86/sev-es: Handle string port IO to kernel memory properlyHyunwook (Wooky) Baek1-0/+12
Don't assume dest/source buffers are userspace addresses when manually copying data for string I/O or MOVS MMIO, as {get,put}_user() will fail if handed a kernel address and ultimately lead to a kernel panic. When invoking INSB/OUTSB instructions in kernel space in a SEV-ES-enabled VM, the kernel crashes with the following message: "SEV-ES: Unsupported exception in #VC instruction emulation - can't continue" Handle that case properly. [ bp: Massage commit message. ] Fixes: f980f9c31a92 ("x86/sev-es: Compile early handler code into kernel image") Signed-off-by: Hyunwook (Wooky) Baek <baekhw@google.com> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: David Rientjes <rientjes@google.com> Link: https://lkml.kernel.org/r/20210110071102.2576186-1-baekhw@google.com
2021-01-10Merge tag 'x86_urgent_for_v5.11_rc3' of ↵Linus Torvalds5-73/+57
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 fixes from Borislav Petkov: "As expected, fixes started trickling in after the holidays so here is the accumulated pile of x86 fixes for 5.11: - A fix for fanotify_mark() missing the conversion of x86_32 native syscalls which take 64-bit arguments to the compat handlers due to former having a general compat handler. (Brian Gerst) - Add a forgotten pmd page destructor call to pud_free_pmd_page() where a pmd page is freed. (Dan Williams) - Make IN/OUT insns with an u8 immediate port operand handling for SEV-ES guests more precise by using only the single port byte and not the whole s32 value of the insn decoder. (Peter Gonda) - Correct a straddling end range check before returning the proper MTRR type, when the end address is the same as top of memory. (Ying-Tsun Huang) - Change PQR_ASSOC MSR update scheme when moving a task to a resctrl resource group to avoid significant performance overhead with some resctrl workloads. (Fenghua Yu) - Avoid the actual task move overhead when the task is already in the resource group. (Fenghua Yu)" * tag 'x86_urgent_for_v5.11_rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/resctrl: Don't move a task to the same resource group x86/resctrl: Use an IPI instead of task_work_add() to update PQR_ASSOC MSR x86/mtrr: Correct the range check before performing MTRR type lookups x86/sev-es: Fix SEV-ES OUT/IN immediate opcode vc handling x86/mm: Fix leak of pmd ptlock fanotify: Fix sys_fanotify_mark() on native x86-32
2021-01-09Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds13-97/+178
Pull kvm fixes from Paolo Bonzini: "x86: - Fixes for the new scalable MMU - Fixes for migration of nested hypervisors on AMD - Fix for clang integrated assembler - Fix for left shift by 64 (UBSAN) - Small cleanups - Straggler SEV-ES patch ARM: - VM init cleanups - PSCI relay cleanups - Kill CONFIG_KVM_ARM_PMU - Fixup __init annotations - Fixup reg_to_encoding() - Fix spurious PMCR_EL0 access Misc: - selftests cleanups" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (38 commits) KVM: x86: __kvm_vcpu_halt can be static KVM: SVM: Add support for booting APs in an SEV-ES guest KVM: nSVM: cancel KVM_REQ_GET_NESTED_STATE_PAGES on nested vmexit KVM: nSVM: mark vmcb as dirty when forcingly leaving the guest mode KVM: nSVM: correctly restore nested_run_pending on migration KVM: x86/mmu: Clarify TDP MMU page list invariants KVM: x86/mmu: Ensure TDP MMU roots are freed after yield kvm: check tlbs_dirty directly KVM: x86: change in pv_eoi_get_pending() to make code more readable MAINTAINERS: Really update email address for Sean Christopherson KVM: x86: fix shift out of bounds reported by UBSAN KVM: selftests: Implement perf_test_util more conventionally KVM: selftests: Use vm_create_with_vcpus in create_vm KVM: selftests: Factor out guest mode code KVM/SVM: Remove leftover __svm_vcpu_run prototype from svm.c KVM: SVM: Add register operand to vmsave call in sev_es_vcpu_load KVM: x86/mmu: Optimize not-present/MMIO SPTE check in get_mmio_spte() KVM: x86/mmu: Use raw level to index into MMIO walks' sptes array KVM: x86/mmu: Get root level from walkers when retrieving MMIO SPTE KVM: x86/mmu: Use -1 to flag an undefined spte in get_mmio_spte() ...
2021-01-08KVM: x86: __kvm_vcpu_halt can be staticPaolo Bonzini1-1/+1
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-01-08x86/resctrl: Don't move a task to the same resource groupFenghua Yu1-0/+7
Shakeel Butt reported in [1] that a user can request a task to be moved to a resource group even if the task is already in the group. It just wastes time to do the move operation which could be costly to send IPI to a different CPU. Add a sanity check to ensure that the move operation only happens when the task is not already in the resource group. [1] https://lore.kernel.org/lkml/CALvZod7E9zzHwenzf7objzGKsdBmVwTgEJ0nPgs0LUFU3SN5Pw@mail.gmail.com/ Fixes: e02737d5b826 ("x86/intel_rdt: Add tasks files") Reported-by: Shakeel Butt <shakeelb@google.com> Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/962ede65d8e95be793cb61102cca37f7bb018e66.1608243147.git.reinette.chatre@intel.com
2021-01-08x86/resctrl: Use an IPI instead of task_work_add() to update PQR_ASSOC MSRFenghua Yu1-69/+43
Currently, when moving a task to a resource group the PQR_ASSOC MSR is updated with the new closid and rmid in an added task callback. If the task is running, the work is run as soon as possible. If the task is not running, the work is executed later in the kernel exit path when the kernel returns to the task again. Updating the PQR_ASSOC MSR as soon as possible on the CPU a moved task is running is the right thing to do. Queueing work for a task that is not running is unnecessary (the PQR_ASSOC MSR is already updated when the task is scheduled in) and causing system resource waste with the way in which it is implemented: Work to update the PQR_ASSOC register is queued every time the user writes a task id to the "tasks" file, even if the task already belongs to the resource group. This could result in multiple pending work items associated with a single task even if they are all identical and even though only a single update with most recent values is needed. Specifically, even if a task is moved between different resource groups while it is sleeping then it is only the last move that is relevant but yet a work item is queued during each move. This unnecessary queueing of work items could result in significant system resource waste, especially on tasks sleeping for a long time. For example, as demonstrated by Shakeel Butt in [1] writing the same task id to the "tasks" file can quickly consume significant memory. The same problem (wasted system resources) occurs when moving a task between different resource groups. As pointed out by Valentin Schneider in [2] there is an additional issue with the way in which the queueing of work is done in that the task_struct update is currently done after the work is queued, resulting in a race with the register update possibly done before the data needed by the update is available. To solve these issues, update the PQR_ASSOC MSR in a synchronous way right after the new closid and rmid are ready during the task movement, only if the task is running. If a moved task is not running nothing is done since the PQR_ASSOC MSR will be updated next time the task is scheduled. This is the same way used to update the register when tasks are moved as part of resource group removal. [1] https://lore.kernel.org/lkml/CALvZod7E9zzHwenzf7objzGKsdBmVwTgEJ0nPgs0LUFU3SN5Pw@mail.gmail.com/ [2] https://lore.kernel.org/lkml/20201123022433.17905-1-valentin.schneider@arm.com [ bp: Massage commit message and drop the two update_task_closid_rmid() variants. ] Fixes: e02737d5b826 ("x86/intel_rdt: Add tasks files") Reported-by: Shakeel Butt <shakeelb@google.com> Reported-by: Valentin Schneider <valentin.schneider@arm.com> Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Reviewed-by: James Morse <james.morse@arm.com> Reviewed-by: Valentin Schneider <valentin.schneider@arm.com> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/17aa2fb38fc12ce7bb710106b3e7c7b45acb9e94.1608243147.git.reinette.chatre@intel.com
2021-01-08KVM: SVM: Add support for booting APs in an SEV-ES guestTom Lendacky7-6/+61
Typically under KVM, an AP is booted using the INIT-SIPI-SIPI sequence, where the guest vCPU register state is updated and then the vCPU is VMRUN to begin execution of the AP. For an SEV-ES guest, this won't work because the guest register state is encrypted. Following the GHCB specification, the hypervisor must not alter the guest register state, so KVM must track an AP/vCPU boot. Should the guest want to park the AP, it must use the AP Reset Hold exit event in place of, for example, a HLT loop. First AP boot (first INIT-SIPI-SIPI sequence): Execute the AP (vCPU) as it was initialized and measured by the SEV-ES support. It is up to the guest to transfer control of the AP to the proper location. Subsequent AP boot: KVM will expect to receive an AP Reset Hold exit event indicating that the vCPU is being parked and will require an INIT-SIPI-SIPI sequence to awaken it. When the AP Reset Hold exit event is received, KVM will place the vCPU into a simulated HLT mode. Upon receiving the INIT-SIPI-SIPI sequence, KVM will make the vCPU runnable. It is again up to the guest to then transfer control of the AP to the proper location. To differentiate between an actual HLT and an AP Reset Hold, a new MP state is introduced, KVM_MP_STATE_AP_RESET_HOLD, which the vCPU is placed in upon receiving the AP Reset Hold exit event. Additionally, to communicate the AP Reset Hold exit event up to userspace (if needed), a new exit reason is introduced, KVM_EXIT_AP_RESET_HOLD. A new x86 ops function is introduced, vcpu_deliver_sipi_vector, in order to accomplish AP booting. For VMX, vcpu_deliver_sipi_vector is set to the original SIPI delivery function, kvm_vcpu_deliver_sipi_vector(). SVM adds a new function that, for non SEV-ES guests, invokes the original SIPI delivery function, kvm_vcpu_deliver_sipi_vector(), but for SEV-ES guests, implements the logic above. Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com> Message-Id: <e8fbebe8eb161ceaabdad7c01a5859a78b424d5e.1609791600.git.thomas.lendacky@amd.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-01-08KVM: nSVM: cancel KVM_REQ_GET_NESTED_STATE_PAGES on nested vmexitMaxim Levitsky3-1/+8
It is possible to exit the nested guest mode, entered by svm_set_nested_state prior to first vm entry to it (e.g due to pending event) if the nested run was not pending during the migration. In this case we must not switch to the nested msr permission bitmap. Also add a warning to catch similar cases in the future. Fixes: a7d5c7ce41ac1 ("KVM: nSVM: delay MSR permission processing to first nested VM run") Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com> Message-Id: <20210107093854.882483-2-mlevitsk@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-01-08KVM: nSVM: mark vmcb as dirty when forcingly leaving the guest modeMaxim Levitsky1-0/+1
We overwrite most of vmcb fields while doing so, so we must mark it as dirty. Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com> Message-Id: <20210107093854.882483-5-mlevitsk@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-01-08KVM: nSVM: correctly restore nested_run_pending on migrationMaxim Levitsky1-0/+4
The code to store it on the migration exists, but no code was restoring it. One of the side effects of fixing this is that L1->L2 injected events are no longer lost when migration happens with nested run pending. Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com> Message-Id: <20210107093854.882483-3-mlevitsk@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-01-08KVM: x86/mmu: Clarify TDP MMU page list invariantsBen Gardon1-2/+14
The tdp_mmu_roots and tdp_mmu_pages in struct kvm_arch should only contain pages with tdp_mmu_page set to true. tdp_mmu_pages should not contain any pages with a non-zero root_count and tdp_mmu_roots should only contain pages with a positive root_count, unless a thread holds the MMU lock and is in the process of modifying the list. Various functions expect these invariants to be maintained, but they are not explictily documented. Add to the comments on both fields to document the above invariants. Signed-off-by: Ben Gardon <bgardon@google.com> Message-Id: <20210107001935.3732070-2-bgardon@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-01-08KVM: x86/mmu: Ensure TDP MMU roots are freed after yieldBen Gardon1-56/+48
Many TDP MMU functions which need to perform some action on all TDP MMU roots hold a reference on that root so that they can safely drop the MMU lock in order to yield to other threads. However, when releasing the reference on the root, there is a bug: the root will not be freed even if its reference count (root_count) is reduced to 0. To simplify acquiring and releasing references on TDP MMU root pages, and to ensure that these roots are properly freed, move the get/put operations into another TDP MMU root iterator macro. Moving the get/put operations into an iterator macro also helps simplify control flow when a root does need to be freed. Note that using the list_for_each_entry_safe macro would not have been appropriate in this situation because it could keep a pointer to the next root across an MMU lock release + reacquire, during which time that root could be freed. Reported-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> Suggested-by: Paolo Bonzini <pbonzini@redhat.com> Fixes: faaf05b00aec ("kvm: x86/mmu: Support zapping SPTEs in the TDP MMU") Fixes: 063afacd8730 ("kvm: x86/mmu: Support invalidate range MMU notifier for TDP MMU") Fixes: a6a0b05da9f3 ("kvm: x86/mmu: Support dirty logging for the TDP MMU") Fixes: 14881998566d ("kvm: x86/mmu: Support disabling dirty logging for the tdp MMU") Signed-off-by: Ben Gardon <bgardon@google.com> Message-Id: <20210107001935.3732070-1-bgardon@google.com> Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-01-08KVM: x86: change in pv_eoi_get_pending() to make code more readableStephen Zhang1-1/+1
Signed-off-by: Stephen Zhang <stephenzhangzsd@gmail.com> Message-Id: <1608277897-1932-1-git-send-email-stephenzhangzsd@gmail.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-01-08KVM: x86: fix shift out of bounds reported by UBSANPaolo Bonzini1-1/+1
Since we know that e >= s, we can reassociate the left shift, changing the shifted number from 1 to 2 in exchange for decreasing the right hand side by 1. Reported-by: syzbot+e87846c48bf72bc85311@syzkaller.appspotmail.com Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-01-08KVM/SVM: Remove leftover __svm_vcpu_run prototype from svm.cUros Bizjak1-2/+0
Commit 16809ecdc1e8a moved __svm_vcpu_run the prototype to svm.h, but forgot to remove the original from svm.c. Fixes: 16809ecdc1e8a ("KVM: SVM: Provide an updated VMRUN invocation for SEV-ES guests") Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Uros Bizjak <ubizjak@gmail.com> Message-Id: <20201220200339.65115-1-ubizjak@gmail.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-01-08KVM: SVM: Add register operand to vmsave call in sev_es_vcpu_loadNathan Chancellor1-1/+1
When using LLVM's integrated assembler (LLVM_IAS=1) while building x86_64_defconfig + CONFIG_KVM=y + CONFIG_KVM_AMD=y, the following build error occurs: $ make LLVM=1 LLVM_IAS=1 arch/x86/kvm/svm/sev.o arch/x86/kvm/svm/sev.c:2004:15: error: too few operands for instruction asm volatile(__ex("vmsave") : : "a" (__sme_page_pa(sd->save_area)) : "memory"); ^ arch/x86/kvm/svm/sev.c:28:17: note: expanded from macro '__ex' #define __ex(x) __kvm_handle_fault_on_reboot(x) ^ ./arch/x86/include/asm/kvm_host.h:1646:10: note: expanded from macro '__kvm_handle_fault_on_reboot' "666: \n\t" \ ^ <inline asm>:2:2: note: instantiated into assembly here vmsave ^ 1 error generated. This happens because LLVM currently does not support calling vmsave without the fixed register operand (%rax for 64-bit and %eax for 32-bit). This will be fixed in LLVM 12 but the kernel currently supports LLVM 10.0.1 and newer so this needs to be handled. Add the proper register using the _ASM_AX macro, which matches the vmsave call in vmenter.S. Fixes: 861377730aa9 ("KVM: SVM: Provide support for SEV-ES vCPU loading") Link: https://reviews.llvm.org/D93524 Link: https://github.com/ClangBuiltLinux/linux/issues/1216 Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> Message-Id: <20201219063711.3526947-1-natechancellor@gmail.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-01-08Merge branch 'kvm-master' into kvm-nextPaolo Bonzini45-297/+331
Fixes to get_mmio_spte, destined to 5.10 stable branch.
2021-01-08KVM: x86/mmu: Optimize not-present/MMIO SPTE check in get_mmio_spte()Sean Christopherson1-7/+13
Check only the terminal leaf for a "!PRESENT || MMIO" SPTE when looking for reserved bits on valid, non-MMIO SPTEs. The get_walk() helpers terminate their walks if a not-present or MMIO SPTE is encountered, i.e. the non-terminal SPTEs have already been verified to be regular SPTEs. This eliminates an extra check-and-branch in a relatively hot loop. Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20201218003139.2167891-5-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-01-08KVM: x86/mmu: Use raw level to index into MMIO walks' sptes arraySean Christopherson2-9/+8
Bump the size of the sptes array by one and use the raw level of the SPTE to index into the sptes array. Using the SPTE level directly improves readability by eliminating the need to reason out why the level is being adjusted when indexing the array. The array is on the stack and is not explicitly initialized; bumping its size is nothing more than a superficial adjustment to the stack frame. Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20201218003139.2167891-4-seanjc@google.com> Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-01-08KVM: x86/mmu: Get root level from walkers when retrieving MMIO SPTESean Christopherson3-11/+13
Get the so called "root" level from the low level shadow page table walkers instead of manually attempting to calculate it higher up the stack, e.g. in get_mmio_spte(). When KVM is using PAE shadow paging, the starting level of the walk, from the callers perspective, is not the CR3 root but rather the PDPTR "root". Checking for reserved bits from the CR3 root causes get_mmio_spte() to consume uninitialized stack data due to indexing into sptes[] for a level that was not filled by get_walk(). This can result in false positives and/or negatives depending on what garbage happens to be on the stack. Opportunistically nuke a few extra newlines. Fixes: 95fb5b0258b7 ("kvm: x86/mmu: Support MMIO in the TDP MMU") Reported-by: Richard Herbert <rherbert@sympatico.ca> Cc: Ben Gardon <bgardon@google.com> Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20201218003139.2167891-3-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-01-08KVM: x86/mmu: Use -1 to flag an undefined spte in get_mmio_spte()Sean Christopherson2-2/+7
Return -1 from the get_walk() helpers if the shadow walk doesn't fill at least one spte, which can theoretically happen if the walk hits a not-present PDPTR. Returning the root level in such a case will cause get_mmio_spte() to return garbage (uninitialized stack data). In practice, such a scenario should be impossible as KVM shouldn't get a reserved-bit page fault with a not-present PDPTR. Note, using mmu->root_level in get_walk() is wrong for other reasons, too, but that's now a moot point. Fixes: 95fb5b0258b7 ("kvm: x86/mmu: Support MMIO in the TDP MMU") Cc: Ben Gardon <bgardon@google.com> Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20201218003139.2167891-2-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-01-06x86/mtrr: Correct the range check before performing MTRR type lookupsYing-Tsun Huang1-3/+3
In mtrr_type_lookup(), if the input memory address region is not in the MTRR, over 4GB, and not over the top of memory, a write-back attribute is returned. These condition checks are for ensuring the input memory address region is actually mapped to the physical memory. However, if the end address is just aligned with the top of memory, the condition check treats the address is over the top of memory, and write-back attribute is not returned. And this hits in a real use case with NVDIMM: the nd_pmem module tries to map NVDIMMs as cacheable memories when NVDIMMs are connected. If a NVDIMM is the last of the DIMMs, the performance of this NVDIMM becomes very low since it is aligned with the top of memory and its memory type is uncached-minus. Move the input end address change to inclusive up into mtrr_type_lookup(), before checking for the top of memory in either mtrr_type_lookup_{variable,fixed}() helpers. [ bp: Massage commit message. ] Fixes: 0cc705f56e40 ("x86/mm/mtrr: Clean up mtrr_type_lookup()") Signed-off-by: Ying-Tsun Huang <ying-tsun.huang@amd.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20201215070721.4349-1-ying-tsun.huang@amd.com
2021-01-06x86/hyperv: check cpu mask after interrupt has been disabledWei Liu1-3/+9
We've observed crashes due to an empty cpu mask in hyperv_flush_tlb_others. Obviously the cpu mask in question is changed between the cpumask_empty call at the beginning of the function and when it is actually used later. One theory is that an interrupt comes in between and a code path ends up changing the mask. Move the check after interrupt has been disabled to see if it fixes the issue. Signed-off-by: Wei Liu <wei.liu@kernel.org> Cc: stable@kernel.org Link: https://lore.kernel.org/r/20210105175043.28325-1-wei.liu@kernel.org Reviewed-by: Michael Kelley <mikelley@microsoft.com>
2021-01-05x86/sev-es: Fix SEV-ES OUT/IN immediate opcode vc handlingPeter Gonda1-2/+2
The IN and OUT instructions with port address as an immediate operand only use an 8-bit immediate (imm8). The current VC handler uses the entire 32-bit immediate value but these instructions only set the first bytes. Cast the operand to an u8 for that. [ bp: Massage commit message. ] Fixes: 25189d08e5168 ("x86/sev-es: Add support for handling IOIO exceptions") Signed-off-by: Peter Gonda <pgonda@google.com> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: David Rientjes <rientjes@google.com> Link: https://lkml.kernel.org/r/20210105163311.221490-1-pgonda@google.com
2021-01-05x86/hyperv: Fix kexec panic/hang issuesDexuan Cui3-0/+24
Currently the kexec kernel can panic or hang due to 2 causes: 1) hv_cpu_die() is not called upon kexec, so the hypervisor corrupts the old VP Assist Pages when the kexec kernel runs. The same issue is fixed for hibernation in commit 421f090c819d ("x86/hyperv: Suspend/resume the VP assist page for hibernation"). Now fix it for kexec. 2) hyperv_cleanup() is called too early. In the kexec path, the other CPUs are stopped in hv_machine_shutdown() -> native_machine_shutdown(), so between hv_kexec_handler() and native_machine_shutdown(), the other CPUs can still try to access the hypercall page and cause panic. The workaround "hv_hypercall_pg = NULL;" in hyperv_cleanup() is unreliabe. Move hyperv_cleanup() to a better place. Signed-off-by: Dexuan Cui <decui@microsoft.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Link: https://lore.kernel.org/r/20201222065541.24312-1-decui@microsoft.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
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