diff options
Diffstat (limited to 'common/recipes-kernel/linux/linux-yocto-4.9.21/0029-KVM-async_pf-Fix-DF-due-to-inject-Page-not-Present-a.patch')
-rw-r--r-- | common/recipes-kernel/linux/linux-yocto-4.9.21/0029-KVM-async_pf-Fix-DF-due-to-inject-Page-not-Present-a.patch | 105 |
1 files changed, 105 insertions, 0 deletions
diff --git a/common/recipes-kernel/linux/linux-yocto-4.9.21/0029-KVM-async_pf-Fix-DF-due-to-inject-Page-not-Present-a.patch b/common/recipes-kernel/linux/linux-yocto-4.9.21/0029-KVM-async_pf-Fix-DF-due-to-inject-Page-not-Present-a.patch new file mode 100644 index 00000000..b50d5453 --- /dev/null +++ b/common/recipes-kernel/linux/linux-yocto-4.9.21/0029-KVM-async_pf-Fix-DF-due-to-inject-Page-not-Present-a.patch @@ -0,0 +1,105 @@ +From 8e13680f134458dd1b0529ccb636ae5895fa8a4d Mon Sep 17 00:00:00 2001 +From: Wanpeng Li <wanpeng.li@hotmail.com> +Date: Thu, 14 Sep 2017 03:54:16 -0700 +Subject: [PATCH 29/33] KVM: async_pf: Fix #DF due to inject "Page not Present" + and "Page Ready" exceptions simultaneously +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +commit 9a6e7c39810e4a8bc7fc95056cefb40583fe07ef upstream. + +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> +[port from upstream v4.14-rc1, Don't assign to kvm_queued_exception::injected or + x86_exception::async_page_fault] +Signed-off-by: Jack Wang <jinpu.wang@profitbricks.com> +Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> +--- + arch/x86/kvm/x86.c | 34 ++++++++++++++++++++++++++-------- + 1 file changed, 26 insertions(+), 8 deletions(-) + +diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c +index af333e1..9f0f7e2 100644 +--- a/arch/x86/kvm/x86.c ++++ b/arch/x86/kvm/x86.c +@@ -8370,6 +8370,13 @@ static int apf_put_user(struct kvm_vcpu *vcpu, u32 val) + sizeof(val)); + } + ++static int apf_get_user(struct kvm_vcpu *vcpu, u32 *val) ++{ ++ ++ return kvm_read_guest_cached(vcpu->kvm, &vcpu->arch.apf.data, val, ++ sizeof(u32)); ++} ++ + void kvm_arch_async_page_not_present(struct kvm_vcpu *vcpu, + struct kvm_async_pf *work) + { +@@ -8396,6 +8403,7 @@ void kvm_arch_async_page_present(struct kvm_vcpu *vcpu, + struct kvm_async_pf *work) + { + struct x86_exception fault; ++ u32 val; + + trace_kvm_async_pf_ready(work->arch.token, work->gva); + if (work->wakeup_all) +@@ -8403,14 +8411,24 @@ void kvm_arch_async_page_present(struct kvm_vcpu *vcpu, + else + kvm_del_async_pf_gfn(vcpu, work->arch.gfn); + +- if ((vcpu->arch.apf.msr_val & KVM_ASYNC_PF_ENABLED) && +- !apf_put_user(vcpu, KVM_PV_REASON_PAGE_READY)) { +- fault.vector = PF_VECTOR; +- fault.error_code_valid = true; +- fault.error_code = 0; +- fault.nested_page_fault = false; +- fault.address = work->arch.token; +- kvm_inject_page_fault(vcpu, &fault); ++ if (vcpu->arch.apf.msr_val & KVM_ASYNC_PF_ENABLED && ++ !apf_get_user(vcpu, &val)) { ++ if (val == KVM_PV_REASON_PAGE_NOT_PRESENT && ++ vcpu->arch.exception.pending && ++ vcpu->arch.exception.nr == PF_VECTOR && ++ !apf_put_user(vcpu, 0)) { ++ vcpu->arch.exception.pending = false; ++ vcpu->arch.exception.nr = 0; ++ vcpu->arch.exception.has_error_code = false; ++ vcpu->arch.exception.error_code = 0; ++ } else if (!apf_put_user(vcpu, KVM_PV_REASON_PAGE_READY)) { ++ fault.vector = PF_VECTOR; ++ fault.error_code_valid = true; ++ fault.error_code = 0; ++ fault.nested_page_fault = false; ++ fault.address = work->arch.token; ++ kvm_inject_page_fault(vcpu, &fault); ++ } + } + vcpu->arch.apf.halted = false; + vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE; +-- +2.7.4 + |