diff options
Diffstat (limited to 'common/recipes-kernel/linux/linux-yocto-4.9.21/0024-KVM-nVMX-Fix-races-when-sending-nested-PI-while-dest.patch')
| -rw-r--r-- | common/recipes-kernel/linux/linux-yocto-4.9.21/0024-KVM-nVMX-Fix-races-when-sending-nested-PI-while-dest.patch | 100 |
1 files changed, 0 insertions, 100 deletions
diff --git a/common/recipes-kernel/linux/linux-yocto-4.9.21/0024-KVM-nVMX-Fix-races-when-sending-nested-PI-while-dest.patch b/common/recipes-kernel/linux/linux-yocto-4.9.21/0024-KVM-nVMX-Fix-races-when-sending-nested-PI-while-dest.patch deleted file mode 100644 index 8feed73a..00000000 --- a/common/recipes-kernel/linux/linux-yocto-4.9.21/0024-KVM-nVMX-Fix-races-when-sending-nested-PI-while-dest.patch +++ /dev/null @@ -1,100 +0,0 @@ -From 36417bad8e288e64df1067207030c67304c26ee5 Mon Sep 17 00:00:00 2001 -From: Liran Alon <liran.alon@oracle.com> -Date: Thu, 9 Nov 2017 20:27:20 +0200 -Subject: [PATCH 24/33] KVM: nVMX: Fix races when sending nested PI while dest - enters/leaves L2 -MIME-Version: 1.0 -Content-Type: text/plain; charset=UTF-8 -Content-Transfer-Encoding: 8bit - -commit 6b6977117f50d60455ace86b2d256f6fb4f3de05 upstream. - -Consider the following scenario: -1. CPU A calls vmx_deliver_nested_posted_interrupt() to send an IPI -to CPU B via virtual posted-interrupt mechanism. -2. CPU B is currently executing L2 guest. -3. vmx_deliver_nested_posted_interrupt() calls -kvm_vcpu_trigger_posted_interrupt() which will note that -vcpu->mode == IN_GUEST_MODE. -4. Assume that before CPU A sends the physical POSTED_INTR_NESTED_VECTOR -IPI, CPU B exits from L2 to L0 during event-delivery -(valid IDT-vectoring-info). -5. CPU A now sends the physical IPI. The IPI is received in host and -it's handler (smp_kvm_posted_intr_nested_ipi()) does nothing. -6. Assume that before CPU A sets pi_pending=true and KVM_REQ_EVENT, -CPU B continues to run in L0 and reach vcpu_enter_guest(). As -KVM_REQ_EVENT is not set yet, vcpu_enter_guest() will continue and resume -L2 guest. -7. At this point, CPU A sets pi_pending=true and KVM_REQ_EVENT but -it's too late! CPU B already entered L2 and KVM_REQ_EVENT will only be -consumed at next L2 entry! - -Another scenario to consider: -1. CPU A calls vmx_deliver_nested_posted_interrupt() to send an IPI -to CPU B via virtual posted-interrupt mechanism. -2. Assume that before CPU A calls kvm_vcpu_trigger_posted_interrupt(), -CPU B is at L0 and is about to resume into L2. Further assume that it is -in vcpu_enter_guest() after check for KVM_REQ_EVENT. -3. At this point, CPU A calls kvm_vcpu_trigger_posted_interrupt() which -will note that vcpu->mode != IN_GUEST_MODE. Therefore, do nothing and -return false. Then, will set pi_pending=true and KVM_REQ_EVENT. -4. Now CPU B continue and resumes into L2 guest without processing -the posted-interrupt until next L2 entry! - -To fix both issues, we just need to change -vmx_deliver_nested_posted_interrupt() to set pi_pending=true and -KVM_REQ_EVENT before calling kvm_vcpu_trigger_posted_interrupt(). - -It will fix the first scenario by chaging step (6) to note that -KVM_REQ_EVENT and pi_pending=true and therefore process -nested posted-interrupt. - -It will fix the second scenario by two possible ways: -1. If kvm_vcpu_trigger_posted_interrupt() is called while CPU B has changed -vcpu->mode to IN_GUEST_MODE, physical IPI will be sent and will be received -when CPU resumes into L2. -2. If kvm_vcpu_trigger_posted_interrupt() is called while CPU B hasn't yet -changed vcpu->mode to IN_GUEST_MODE, then after CPU B will change -vcpu->mode it will call kvm_request_pending() which will return true and -therefore force another round of vcpu_enter_guest() which will note that -KVM_REQ_EVENT and pi_pending=true and therefore process nested -posted-interrupt. - -Fixes: 705699a13994 ("KVM: nVMX: Enable nested posted interrupt processing") -Signed-off-by: Liran Alon <liran.alon@oracle.com> -Reviewed-by: Nikita Leshenko <nikita.leshchenko@oracle.com> -Reviewed-by: Krish Sadhukhan <krish.sadhukhan@oracle.com> -[Add kvm_vcpu_kick to also handle the case where L1 doesn't intercept L2 HLT - and L2 executes HLT instruction. - Paolo] -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> ---- - arch/x86/kvm/vmx.c | 5 +++-- - 1 file changed, 3 insertions(+), 2 deletions(-) - -diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c -index c564d03..85078c7 100644 ---- a/arch/x86/kvm/vmx.c -+++ b/arch/x86/kvm/vmx.c -@@ -4944,14 +4944,15 @@ static int vmx_deliver_nested_posted_interrupt(struct kvm_vcpu *vcpu, - - if (is_guest_mode(vcpu) && - vector == vmx->nested.posted_intr_nv) { -- /* the PIR and ON have been set by L1. */ -- kvm_vcpu_trigger_posted_interrupt(vcpu); - /* - * If a posted intr is not recognized by hardware, - * we will accomplish it in the next vmentry. - */ - vmx->nested.pi_pending = true; - kvm_make_request(KVM_REQ_EVENT, vcpu); -+ /* the PIR and ON have been set by L1. */ -+ if (!kvm_vcpu_trigger_posted_interrupt(vcpu)) -+ kvm_vcpu_kick(vcpu); - return 0; - } - return -1; --- -2.7.4 - |