* [PATCH 1/2] KVM: Pass MMU notifier range flags to kvm_unmap_hva_range() [not found] <20200811102725.7121-1-will@kernel.org> @ 2020-08-11 10:27 ` Will Deacon 2020-08-19 23:57 ` Sasha Levin 2020-08-26 13:54 ` Sasha Levin 2020-08-11 10:27 ` [PATCH 2/2] KVM: arm64: Only reschedule if MMU_NOTIFIER_RANGE_BLOCKABLE is not set Will Deacon 1 sibling, 2 replies; 5+ messages in thread From: Will Deacon @ 2020-08-11 10:27 UTC (permalink / raw) To: kvmarm, linux-kernel, kvm Cc: Will Deacon, Marc Zyngier, Suzuki K Poulose, James Morse, Thomas Bogendoerfer, Paul Mackerras, Paolo Bonzini, Sean Christopherson, stable The 'flags' field of 'struct mmu_notifier_range' is used to indicate whether invalidate_range_{start,end}() are permitted to block. In the case of kvm_mmu_notifier_invalidate_range_start(), this field is not forwarded on to the architecture-specific implementation of kvm_unmap_hva_range() and therefore the backend cannot sensibly decide whether or not to block. Add an extra 'flags' parameter to kvm_unmap_hva_range() so that architectures are aware as to whether or not they are permitted to block. Cc: <stable@vger.kernel.org> Cc: Marc Zyngier <maz@kernel.org> Cc: Suzuki K Poulose <suzuki.poulose@arm.com> Cc: James Morse <james.morse@arm.com> Signed-off-by: Will Deacon <will@kernel.org> --- arch/arm64/include/asm/kvm_host.h | 2 +- arch/arm64/kvm/mmu.c | 2 +- arch/mips/include/asm/kvm_host.h | 2 +- arch/mips/kvm/mmu.c | 3 ++- arch/powerpc/include/asm/kvm_host.h | 3 ++- arch/powerpc/kvm/book3s.c | 3 ++- arch/powerpc/kvm/e500_mmu_host.c | 3 ++- arch/x86/include/asm/kvm_host.h | 3 ++- arch/x86/kvm/mmu/mmu.c | 3 ++- virt/kvm/kvm_main.c | 3 ++- 10 files changed, 17 insertions(+), 10 deletions(-) diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index e21d4a01372f..759d62343e1d 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -443,7 +443,7 @@ int __kvm_arm_vcpu_set_events(struct kvm_vcpu *vcpu, #define KVM_ARCH_WANT_MMU_NOTIFIER int kvm_unmap_hva_range(struct kvm *kvm, - unsigned long start, unsigned long end); + unsigned long start, unsigned long end, unsigned flags); int kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte); int kvm_age_hva(struct kvm *kvm, unsigned long start, unsigned long end); int kvm_test_age_hva(struct kvm *kvm, unsigned long hva); diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index 31058e6e7c2a..5f6b35c33618 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -2203,7 +2203,7 @@ static int kvm_unmap_hva_handler(struct kvm *kvm, gpa_t gpa, u64 size, void *dat } int kvm_unmap_hva_range(struct kvm *kvm, - unsigned long start, unsigned long end) + unsigned long start, unsigned long end, unsigned flags) { if (!kvm->arch.pgd) return 0; diff --git a/arch/mips/include/asm/kvm_host.h b/arch/mips/include/asm/kvm_host.h index 363e7a89d173..ef1d25d49ec8 100644 --- a/arch/mips/include/asm/kvm_host.h +++ b/arch/mips/include/asm/kvm_host.h @@ -981,7 +981,7 @@ enum kvm_mips_fault_result kvm_trap_emul_gva_fault(struct kvm_vcpu *vcpu, #define KVM_ARCH_WANT_MMU_NOTIFIER int kvm_unmap_hva_range(struct kvm *kvm, - unsigned long start, unsigned long end); + unsigned long start, unsigned long end, unsigned flags); int kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte); int kvm_age_hva(struct kvm *kvm, unsigned long start, unsigned long end); int kvm_test_age_hva(struct kvm *kvm, unsigned long hva); diff --git a/arch/mips/kvm/mmu.c b/arch/mips/kvm/mmu.c index 49bd160f4d85..0783ac9b3240 100644 --- a/arch/mips/kvm/mmu.c +++ b/arch/mips/kvm/mmu.c @@ -518,7 +518,8 @@ static int kvm_unmap_hva_handler(struct kvm *kvm, gfn_t gfn, gfn_t gfn_end, return 1; } -int kvm_unmap_hva_range(struct kvm *kvm, unsigned long start, unsigned long end) +int kvm_unmap_hva_range(struct kvm *kvm, unsigned long start, unsigned long end, + unsigned flags) { handle_hva_to_gpa(kvm, start, end, &kvm_unmap_hva_handler, NULL); diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h index 7e2d061d0445..bccf0ba2da2e 100644 --- a/arch/powerpc/include/asm/kvm_host.h +++ b/arch/powerpc/include/asm/kvm_host.h @@ -58,7 +58,8 @@ #define KVM_ARCH_WANT_MMU_NOTIFIER extern int kvm_unmap_hva_range(struct kvm *kvm, - unsigned long start, unsigned long end); + unsigned long start, unsigned long end, + unsigned flags); extern int kvm_age_hva(struct kvm *kvm, unsigned long start, unsigned long end); extern int kvm_test_age_hva(struct kvm *kvm, unsigned long hva); extern int kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte); diff --git a/arch/powerpc/kvm/book3s.c b/arch/powerpc/kvm/book3s.c index 41fedec69ac3..49db50d1db04 100644 --- a/arch/powerpc/kvm/book3s.c +++ b/arch/powerpc/kvm/book3s.c @@ -834,7 +834,8 @@ void kvmppc_core_commit_memory_region(struct kvm *kvm, kvm->arch.kvm_ops->commit_memory_region(kvm, mem, old, new, change); } -int kvm_unmap_hva_range(struct kvm *kvm, unsigned long start, unsigned long end) +int kvm_unmap_hva_range(struct kvm *kvm, unsigned long start, unsigned long end, + unsigned flags) { return kvm->arch.kvm_ops->unmap_hva_range(kvm, start, end); } diff --git a/arch/powerpc/kvm/e500_mmu_host.c b/arch/powerpc/kvm/e500_mmu_host.c index d6c1069e9954..ed0c9c43d0cf 100644 --- a/arch/powerpc/kvm/e500_mmu_host.c +++ b/arch/powerpc/kvm/e500_mmu_host.c @@ -734,7 +734,8 @@ static int kvm_unmap_hva(struct kvm *kvm, unsigned long hva) return 0; } -int kvm_unmap_hva_range(struct kvm *kvm, unsigned long start, unsigned long end) +int kvm_unmap_hva_range(struct kvm *kvm, unsigned long start, unsigned long end, + unsigned flags) { /* kvm_unmap_hva flushes everything anyways */ kvm_unmap_hva(kvm, start); diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index be5363b21540..c6908a3d551e 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1641,7 +1641,8 @@ asmlinkage void kvm_spurious_fault(void); _ASM_EXTABLE(666b, 667b) #define KVM_ARCH_WANT_MMU_NOTIFIER -int kvm_unmap_hva_range(struct kvm *kvm, unsigned long start, unsigned long end); +int kvm_unmap_hva_range(struct kvm *kvm, unsigned long start, unsigned long end, + unsigned flags); int kvm_age_hva(struct kvm *kvm, unsigned long start, unsigned long end); int kvm_test_age_hva(struct kvm *kvm, unsigned long hva); int kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte); diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 6d6a0ae7800c..9516a958e780 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -1971,7 +1971,8 @@ static int kvm_handle_hva(struct kvm *kvm, unsigned long hva, return kvm_handle_hva_range(kvm, hva, hva + 1, data, handler); } -int kvm_unmap_hva_range(struct kvm *kvm, unsigned long start, unsigned long end) +int kvm_unmap_hva_range(struct kvm *kvm, unsigned long start, unsigned long end, + unsigned flags) { return kvm_handle_hva_range(kvm, start, end, 0, kvm_unmap_rmapp); } diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 0a68c9d3d3ab..9e925675a886 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -427,7 +427,8 @@ static int kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn, * count is also read inside the mmu_lock critical section. */ kvm->mmu_notifier_count++; - need_tlb_flush = kvm_unmap_hva_range(kvm, range->start, range->end); + need_tlb_flush = kvm_unmap_hva_range(kvm, range->start, range->end, + range->flags); need_tlb_flush |= kvm->tlbs_dirty; /* we've to flush the tlb before the pages can be freed */ if (need_tlb_flush) -- 2.28.0.236.gb10cc79966-goog ^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH 1/2] KVM: Pass MMU notifier range flags to kvm_unmap_hva_range() 2020-08-11 10:27 ` [PATCH 1/2] KVM: Pass MMU notifier range flags to kvm_unmap_hva_range() Will Deacon @ 2020-08-19 23:57 ` Sasha Levin 2020-08-26 13:54 ` Sasha Levin 1 sibling, 0 replies; 5+ messages in thread From: Sasha Levin @ 2020-08-19 23:57 UTC (permalink / raw) To: Sasha Levin, Will Deacon, kvmarm, linux-kernel Cc: Will Deacon, Marc Zyngier, stable, Marc Zyngier, Suzuki K Poulose, James Morse, stable Hi [This is an automated email] This commit has been processed because it contains a -stable tag. The stable tag indicates that it's relevant for the following trees: all The bot has tested the following trees: v5.8.1, v5.7.15, v5.4.58, v4.19.139, v4.14.193, v4.9.232, v4.4.232. v5.8.1: Build OK! v5.7.15: Build OK! v5.4.58: Build OK! v4.19.139: Failed to apply! Possible dependencies: 18fc7bf8e041 ("arm64: KVM: Allow for direct call of HYP functions when using VHE") 208243c752a7 ("KVM: arm64: Move hyp-init.S to nVHE") 25357de01b95 ("KVM: arm64: Clean up kvm makefiles") 33e45234987e ("arm64: initialize and switch ptrauth kernel keys") 396244692232 ("arm64: preempt: Provide our own implementation of asm/preempt.h") 3f58bf634555 ("KVM: arm/arm64: Share common code in user_mem_abort()") 6396b852e46e ("KVM: arm/arm64: Re-factor setting the Stage 2 entry to exec on fault") 748c0e312fce ("KVM: Make kvm_set_spte_hva() return int") 750319756256 ("arm64: add basic pointer authentication support") 7621712918ad ("KVM: arm64: Add build rules for separate VHE/nVHE object files") 7aa8d1464165 ("arm/arm64: KVM: Introduce kvm_call_hyp_ret()") 86d0dd34eaff ("arm64: cpufeature: add feature for CRC32 instructions") 90776dd1c427 ("arm64/efi: Move variable assignments after SECTIONS") 95b861a4a6d9 ("arm64: arch_timer: Add workaround for ARM erratum 1188873") a0e50aa3f4a8 ("KVM: arm64: Factor out stage 2 page table data from struct kvm") b877e9849d41 ("KVM: arm64: Build hyp-entry.S separately for VHE/nVHE") bd4fb6d270bc ("arm64: Add support for SB barrier and patch in over DSB; ISB sequences") be1298425665 ("arm64: install user ptrauth keys at kernel exit time") d82755b2e781 ("KVM: arm64: Kill off CONFIG_KVM_ARM_HOST") f50b6f6ae131 ("KVM: arm64: Handle calls to prefixed hyp functions") f56063c51f9f ("arm64: add image head flag definitions") f8df73388ee2 ("KVM: arm/arm64: Introduce helpers to manipulate page table entries") v4.14.193: Failed to apply! Possible dependencies: 0db9dd8a0fbd ("KVM: arm/arm64: Stop using the kernel's {pmd,pud,pgd}_populate helpers") 17ab9d57deba ("KVM: arm/arm64: Drop vcpu parameter from guest cache maintenance operartions") 3f58bf634555 ("KVM: arm/arm64: Share common code in user_mem_abort()") 6396b852e46e ("KVM: arm/arm64: Re-factor setting the Stage 2 entry to exec on fault") 694556d54f35 ("KVM: arm/arm64: Clean dcache to PoC when changing PTE due to CoW") 748c0e312fce ("KVM: Make kvm_set_spte_hva() return int") 88dc25e8ea7c ("KVM: arm/arm64: Consolidate page-table accessors") 91c703e0382a ("arm: KVM: Add optimized PIPT icache flushing") a15f693935a9 ("KVM: arm/arm64: Split dcache/icache flushing") a9c0e12ebee5 ("KVM: arm/arm64: Only clean the dcache on translation fault") d0e22b4ac3ba ("KVM: arm/arm64: Limit icache invalidation to prefetch aborts") f8df73388ee2 ("KVM: arm/arm64: Introduce helpers to manipulate page table entries") v4.9.232: Failed to apply! Possible dependencies: 1534b3964901 ("KVM: MIPS/MMU: Simplify ASID restoration") 1581ff3dbf69 ("KVM: MIPS/MMU: Move preempt/ASID handling to implementation") 1880afd6057f ("KVM: MIPS/T&E: Add lockless GVA access helpers") 411740f5422a ("KVM: MIPS/MMU: Implement KVM_CAP_SYNC_MMU") 748c0e312fce ("KVM: Make kvm_set_spte_hva() return int") 91cdee5710d5 ("KVM: MIPS/T&E: Restore host asid on return to host") a2c046e40ff1 ("KVM: MIPS: Add vcpu_run() & vcpu_reenter() callbacks") a31b50d741bd ("KVM: MIPS/MMU: Invalidate GVA PTs on ASID changes") a60b8438bdba ("KVM: MIPS: Convert get/set_regs -> vcpu_load/put") a7ebb2e410f8 ("KVM: MIPS/T&E: active_mm = init_mm in guest context") aba8592950f1 ("KVM: MIPS/MMU: Invalidate stale GVA PTEs on TLBW") c550d53934d8 ("KVM: MIPS: Remove duplicated ASIDs from vcpu") v4.4.232: Failed to apply! Possible dependencies: 16d100db245a ("MIPS: Move Cause.ExcCode trap codes to mipsregs.h") 1880afd6057f ("KVM: MIPS/T&E: Add lockless GVA access helpers") 19d194c62b25 ("MIPS: KVM: Simplify TLB_* macros") 411740f5422a ("KVM: MIPS/MMU: Implement KVM_CAP_SYNC_MMU") 748c0e312fce ("KVM: Make kvm_set_spte_hva() return int") 8cffd1974851 ("MIPS: KVM: Convert code to kernel sized types") 9fbfb06a4065 ("MIPS: KVM: Arrayify struct kvm_mips_tlb::tlb_lo*") ba049e93aef7 ("kvm: rename pfn_t to kvm_pfn_t") bdb7ed8608f8 ("MIPS: KVM: Convert headers to kernel sized types") ca64c2beecd4 ("MIPS: KVM: Abstract guest ASID mask") caa1faa7aba6 ("MIPS: KVM: Trivial whitespace and style fixes") NOTE: The patch will not be queued to stable trees until it is upstream. How should we proceed with this patch? -- Thanks Sasha ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH 1/2] KVM: Pass MMU notifier range flags to kvm_unmap_hva_range() 2020-08-11 10:27 ` [PATCH 1/2] KVM: Pass MMU notifier range flags to kvm_unmap_hva_range() Will Deacon 2020-08-19 23:57 ` Sasha Levin @ 2020-08-26 13:54 ` Sasha Levin 1 sibling, 0 replies; 5+ messages in thread From: Sasha Levin @ 2020-08-26 13:54 UTC (permalink / raw) To: Sasha Levin, Will Deacon, kvmarm, linux-kernel Cc: Will Deacon, Marc Zyngier, stable, Marc Zyngier, Suzuki K Poulose, James Morse, stable Hi [This is an automated email] This commit has been processed because it contains a -stable tag. The stable tag indicates that it's relevant for the following trees: all The bot has tested the following trees: v5.8.2, v5.7.16, v5.4.59, v4.19.140, v4.14.193, v4.9.232, v4.4.232. v5.8.2: Build OK! v5.7.16: Build OK! v5.4.59: Build OK! v4.19.140: Failed to apply! Possible dependencies: 18fc7bf8e041 ("arm64: KVM: Allow for direct call of HYP functions when using VHE") 208243c752a7 ("KVM: arm64: Move hyp-init.S to nVHE") 25357de01b95 ("KVM: arm64: Clean up kvm makefiles") 33e45234987e ("arm64: initialize and switch ptrauth kernel keys") 396244692232 ("arm64: preempt: Provide our own implementation of asm/preempt.h") 3f58bf634555 ("KVM: arm/arm64: Share common code in user_mem_abort()") 6396b852e46e ("KVM: arm/arm64: Re-factor setting the Stage 2 entry to exec on fault") 748c0e312fce ("KVM: Make kvm_set_spte_hva() return int") 750319756256 ("arm64: add basic pointer authentication support") 7621712918ad ("KVM: arm64: Add build rules for separate VHE/nVHE object files") 7aa8d1464165 ("arm/arm64: KVM: Introduce kvm_call_hyp_ret()") 86d0dd34eaff ("arm64: cpufeature: add feature for CRC32 instructions") 90776dd1c427 ("arm64/efi: Move variable assignments after SECTIONS") 95b861a4a6d9 ("arm64: arch_timer: Add workaround for ARM erratum 1188873") a0e50aa3f4a8 ("KVM: arm64: Factor out stage 2 page table data from struct kvm") b877e9849d41 ("KVM: arm64: Build hyp-entry.S separately for VHE/nVHE") bd4fb6d270bc ("arm64: Add support for SB barrier and patch in over DSB; ISB sequences") be1298425665 ("arm64: install user ptrauth keys at kernel exit time") d82755b2e781 ("KVM: arm64: Kill off CONFIG_KVM_ARM_HOST") f50b6f6ae131 ("KVM: arm64: Handle calls to prefixed hyp functions") f56063c51f9f ("arm64: add image head flag definitions") f8df73388ee2 ("KVM: arm/arm64: Introduce helpers to manipulate page table entries") v4.14.193: Failed to apply! Possible dependencies: 0db9dd8a0fbd ("KVM: arm/arm64: Stop using the kernel's {pmd,pud,pgd}_populate helpers") 17ab9d57deba ("KVM: arm/arm64: Drop vcpu parameter from guest cache maintenance operartions") 3f58bf634555 ("KVM: arm/arm64: Share common code in user_mem_abort()") 6396b852e46e ("KVM: arm/arm64: Re-factor setting the Stage 2 entry to exec on fault") 694556d54f35 ("KVM: arm/arm64: Clean dcache to PoC when changing PTE due to CoW") 748c0e312fce ("KVM: Make kvm_set_spte_hva() return int") 88dc25e8ea7c ("KVM: arm/arm64: Consolidate page-table accessors") 91c703e0382a ("arm: KVM: Add optimized PIPT icache flushing") a15f693935a9 ("KVM: arm/arm64: Split dcache/icache flushing") a9c0e12ebee5 ("KVM: arm/arm64: Only clean the dcache on translation fault") d0e22b4ac3ba ("KVM: arm/arm64: Limit icache invalidation to prefetch aborts") f8df73388ee2 ("KVM: arm/arm64: Introduce helpers to manipulate page table entries") v4.9.232: Failed to apply! Possible dependencies: 1534b3964901 ("KVM: MIPS/MMU: Simplify ASID restoration") 1581ff3dbf69 ("KVM: MIPS/MMU: Move preempt/ASID handling to implementation") 1880afd6057f ("KVM: MIPS/T&E: Add lockless GVA access helpers") 411740f5422a ("KVM: MIPS/MMU: Implement KVM_CAP_SYNC_MMU") 748c0e312fce ("KVM: Make kvm_set_spte_hva() return int") 91cdee5710d5 ("KVM: MIPS/T&E: Restore host asid on return to host") a2c046e40ff1 ("KVM: MIPS: Add vcpu_run() & vcpu_reenter() callbacks") a31b50d741bd ("KVM: MIPS/MMU: Invalidate GVA PTs on ASID changes") a60b8438bdba ("KVM: MIPS: Convert get/set_regs -> vcpu_load/put") a7ebb2e410f8 ("KVM: MIPS/T&E: active_mm = init_mm in guest context") aba8592950f1 ("KVM: MIPS/MMU: Invalidate stale GVA PTEs on TLBW") c550d53934d8 ("KVM: MIPS: Remove duplicated ASIDs from vcpu") v4.4.232: Failed to apply! Possible dependencies: 16d100db245a ("MIPS: Move Cause.ExcCode trap codes to mipsregs.h") 1880afd6057f ("KVM: MIPS/T&E: Add lockless GVA access helpers") 19d194c62b25 ("MIPS: KVM: Simplify TLB_* macros") 411740f5422a ("KVM: MIPS/MMU: Implement KVM_CAP_SYNC_MMU") 748c0e312fce ("KVM: Make kvm_set_spte_hva() return int") 8cffd1974851 ("MIPS: KVM: Convert code to kernel sized types") 9fbfb06a4065 ("MIPS: KVM: Arrayify struct kvm_mips_tlb::tlb_lo*") ba049e93aef7 ("kvm: rename pfn_t to kvm_pfn_t") bdb7ed8608f8 ("MIPS: KVM: Convert headers to kernel sized types") ca64c2beecd4 ("MIPS: KVM: Abstract guest ASID mask") caa1faa7aba6 ("MIPS: KVM: Trivial whitespace and style fixes") NOTE: The patch will not be queued to stable trees until it is upstream. How should we proceed with this patch? -- Thanks Sasha ^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH 2/2] KVM: arm64: Only reschedule if MMU_NOTIFIER_RANGE_BLOCKABLE is not set [not found] <20200811102725.7121-1-will@kernel.org> 2020-08-11 10:27 ` [PATCH 1/2] KVM: Pass MMU notifier range flags to kvm_unmap_hva_range() Will Deacon @ 2020-08-11 10:27 ` Will Deacon 2020-08-11 10:52 ` Suzuki K Poulose 1 sibling, 1 reply; 5+ messages in thread From: Will Deacon @ 2020-08-11 10:27 UTC (permalink / raw) To: kvmarm, linux-kernel, kvm Cc: Will Deacon, Marc Zyngier, Suzuki K Poulose, James Morse, Thomas Bogendoerfer, Paul Mackerras, Paolo Bonzini, Sean Christopherson, stable When an MMU notifier call results in unmapping a range that spans multiple PGDs, we end up calling into cond_resched_lock() when crossing a PGD boundary, since this avoids running into RCU stalls during VM teardown. Unfortunately, if the VM is destroyed as a result of OOM, then blocking is not permitted and the call to the scheduler triggers the following BUG(): | BUG: sleeping function called from invalid context at arch/arm64/kvm/mmu.c:394 | in_atomic(): 1, irqs_disabled(): 0, non_block: 1, pid: 36, name: oom_reaper | INFO: lockdep is turned off. | CPU: 3 PID: 36 Comm: oom_reaper Not tainted 5.8.0 #1 | Hardware name: QEMU QEMU Virtual Machine, BIOS 0.0.0 02/06/2015 | Call trace: | dump_backtrace+0x0/0x284 | show_stack+0x1c/0x28 | dump_stack+0xf0/0x1a4 | ___might_sleep+0x2bc/0x2cc | unmap_stage2_range+0x160/0x1ac | kvm_unmap_hva_range+0x1a0/0x1c8 | kvm_mmu_notifier_invalidate_range_start+0x8c/0xf8 | __mmu_notifier_invalidate_range_start+0x218/0x31c | mmu_notifier_invalidate_range_start_nonblock+0x78/0xb0 | __oom_reap_task_mm+0x128/0x268 | oom_reap_task+0xac/0x298 | oom_reaper+0x178/0x17c | kthread+0x1e4/0x1fc | ret_from_fork+0x10/0x30 Use the new 'flags' argument to kvm_unmap_hva_range() to ensure that we only reschedule if MMU_NOTIFIER_RANGE_BLOCKABLE is set in the notifier flags. Cc: <stable@vger.kernel.org> Fixes: 8b3405e345b5 ("kvm: arm/arm64: Fix locking for kvm_free_stage2_pgd") Cc: Marc Zyngier <maz@kernel.org> Cc: Suzuki K Poulose <suzuki.poulose@arm.com> Cc: James Morse <james.morse@arm.com> Signed-off-by: Will Deacon <will@kernel.org> --- arch/arm64/kvm/mmu.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-) diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index 5f6b35c33618..bd47f06739d6 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -365,7 +365,8 @@ static void unmap_stage2_p4ds(struct kvm *kvm, pgd_t *pgd, * destroying the VM), otherwise another faulting VCPU may come in and mess * with things behind our backs. */ -static void unmap_stage2_range(struct kvm *kvm, phys_addr_t start, u64 size) +static void __unmap_stage2_range(struct kvm *kvm, phys_addr_t start, u64 size, + bool may_block) { pgd_t *pgd; phys_addr_t addr = start, end = start + size; @@ -390,11 +391,16 @@ static void unmap_stage2_range(struct kvm *kvm, phys_addr_t start, u64 size) * If the range is too large, release the kvm->mmu_lock * to prevent starvation and lockup detector warnings. */ - if (next != end) + if (may_block && next != end) cond_resched_lock(&kvm->mmu_lock); } while (pgd++, addr = next, addr != end); } +static void unmap_stage2_range(struct kvm *kvm, phys_addr_t start, u64 size) +{ + __unmap_stage2_range(kvm, start, size, true); +} + static void stage2_flush_ptes(struct kvm *kvm, pmd_t *pmd, phys_addr_t addr, phys_addr_t end) { @@ -2198,7 +2204,10 @@ static int handle_hva_to_gpa(struct kvm *kvm, static int kvm_unmap_hva_handler(struct kvm *kvm, gpa_t gpa, u64 size, void *data) { - unmap_stage2_range(kvm, gpa, size); + unsigned flags = *(unsigned *)data; + bool may_block = flags & MMU_NOTIFIER_RANGE_BLOCKABLE; + + __unmap_stage2_range(kvm, gpa, size, may_block); return 0; } @@ -2209,7 +2218,7 @@ int kvm_unmap_hva_range(struct kvm *kvm, return 0; trace_kvm_unmap_hva_range(start, end); - handle_hva_to_gpa(kvm, start, end, &kvm_unmap_hva_handler, NULL); + handle_hva_to_gpa(kvm, start, end, &kvm_unmap_hva_handler, &flags); return 0; } -- 2.28.0.236.gb10cc79966-goog ^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH 2/2] KVM: arm64: Only reschedule if MMU_NOTIFIER_RANGE_BLOCKABLE is not set 2020-08-11 10:27 ` [PATCH 2/2] KVM: arm64: Only reschedule if MMU_NOTIFIER_RANGE_BLOCKABLE is not set Will Deacon @ 2020-08-11 10:52 ` Suzuki K Poulose 0 siblings, 0 replies; 5+ messages in thread From: Suzuki K Poulose @ 2020-08-11 10:52 UTC (permalink / raw) To: will, kvmarm, linux-kernel, kvm Cc: maz, james.morse, tsbogend, paulus, pbonzini, sean.j.christopherson, stable On 08/11/2020 11:27 AM, Will Deacon wrote: > When an MMU notifier call results in unmapping a range that spans multiple > PGDs, we end up calling into cond_resched_lock() when crossing a PGD boundary, > since this avoids running into RCU stalls during VM teardown. Unfortunately, > if the VM is destroyed as a result of OOM, then blocking is not permitted > and the call to the scheduler triggers the following BUG(): > > | BUG: sleeping function called from invalid context at arch/arm64/kvm/mmu.c:394 > | in_atomic(): 1, irqs_disabled(): 0, non_block: 1, pid: 36, name: oom_reaper > | INFO: lockdep is turned off. > | CPU: 3 PID: 36 Comm: oom_reaper Not tainted 5.8.0 #1 > | Hardware name: QEMU QEMU Virtual Machine, BIOS 0.0.0 02/06/2015 > | Call trace: > | dump_backtrace+0x0/0x284 > | show_stack+0x1c/0x28 > | dump_stack+0xf0/0x1a4 > | ___might_sleep+0x2bc/0x2cc > | unmap_stage2_range+0x160/0x1ac > | kvm_unmap_hva_range+0x1a0/0x1c8 > | kvm_mmu_notifier_invalidate_range_start+0x8c/0xf8 > | __mmu_notifier_invalidate_range_start+0x218/0x31c > | mmu_notifier_invalidate_range_start_nonblock+0x78/0xb0 > | __oom_reap_task_mm+0x128/0x268 > | oom_reap_task+0xac/0x298 > | oom_reaper+0x178/0x17c > | kthread+0x1e4/0x1fc > | ret_from_fork+0x10/0x30 > > Use the new 'flags' argument to kvm_unmap_hva_range() to ensure that we > only reschedule if MMU_NOTIFIER_RANGE_BLOCKABLE is set in the notifier > flags. > > Cc: <stable@vger.kernel.org> > Fixes: 8b3405e345b5 ("kvm: arm/arm64: Fix locking for kvm_free_stage2_pgd") > Cc: Marc Zyngier <maz@kernel.org> > Cc: Suzuki K Poulose <suzuki.poulose@arm.com> > Cc: James Morse <james.morse@arm.com> > Signed-off-by: Will Deacon <will@kernel.org> > --- Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> ^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2020-08-26 13:54 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
[not found] <20200811102725.7121-1-will@kernel.org>
2020-08-11 10:27 ` [PATCH 1/2] KVM: Pass MMU notifier range flags to kvm_unmap_hva_range() Will Deacon
2020-08-19 23:57 ` Sasha Levin
2020-08-26 13:54 ` Sasha Levin
2020-08-11 10:27 ` [PATCH 2/2] KVM: arm64: Only reschedule if MMU_NOTIFIER_RANGE_BLOCKABLE is not set Will Deacon
2020-08-11 10:52 ` Suzuki K Poulose
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for NNTP newsgroup(s).