diff options
Diffstat (limited to 'common/recipes-kernel/linux/linux-yocto-4.9.21/0015-KVM-SVM-do-not-zero-out-segment-attributes-if-segmen.patch')
| -rw-r--r-- | common/recipes-kernel/linux/linux-yocto-4.9.21/0015-KVM-SVM-do-not-zero-out-segment-attributes-if-segmen.patch | 95 |
1 files changed, 0 insertions, 95 deletions
diff --git a/common/recipes-kernel/linux/linux-yocto-4.9.21/0015-KVM-SVM-do-not-zero-out-segment-attributes-if-segmen.patch b/common/recipes-kernel/linux/linux-yocto-4.9.21/0015-KVM-SVM-do-not-zero-out-segment-attributes-if-segmen.patch deleted file mode 100644 index 913e3fe5..00000000 --- a/common/recipes-kernel/linux/linux-yocto-4.9.21/0015-KVM-SVM-do-not-zero-out-segment-attributes-if-segmen.patch +++ /dev/null @@ -1,95 +0,0 @@ -From 348032cf73954af79ac077ae0c13d6faa99294af Mon Sep 17 00:00:00 2001 -From: Roman Pen <roman.penyaev@profitbricks.com> -Date: Thu, 1 Jun 2017 10:55:03 +0200 -Subject: [PATCH 15/93] KVM: SVM: do not zero out segment attributes if segment - is unusable or not present -MIME-Version: 1.0 -Content-Type: text/plain; charset=UTF-8 -Content-Transfer-Encoding: 8bit - -[ Upstream commit d9c1b5431d5f0e07575db785a022bce91051ac1d ] - -This is a fix for the problem [1], where VMCB.CPL was set to 0 and interrupt -was taken on userspace stack. The root cause lies in the specific AMD CPU -behaviour which manifests itself as unusable segment attributes on SYSRET. -The corresponding work around for the kernel is the following: - -61f01dd941ba ("x86_64, asm: Work around AMD SYSRET SS descriptor attribute issue") - -In other turn virtualization side treated unusable segment incorrectly and -restored CPL from SS attributes, which were zeroed out few lines above. - -In current patch it is assured only that P bit is cleared in VMCB.save state -and segment attributes are not zeroed out if segment is not presented or is -unusable, therefore CPL can be safely restored from DPL field. - -This is only one part of the fix, since QEMU side should be fixed accordingly -not to zero out attributes on its side. Corresponding patch will follow. - -[1] Message id: CAJrWOzD6Xq==b-zYCDdFLgSRMPM-NkNuTSDFEtX=7MreT45i7Q@mail.gmail.com - -Signed-off-by: Roman Pen <roman.penyaev@profitbricks.com> -Signed-off-by: Mikhail Sennikovskii <mikhail.sennikovskii@profitbricks.com> -Cc: Paolo Bonzini <pbonzini@redhat.com> -Cc: Radim KrÄmář <rkrcmar@redhat.com> -Cc: kvm@vger.kernel.org -Cc: linux-kernel@vger.kernel.org -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> ---- - arch/x86/kvm/svm.c | 24 +++++++++++------------- - 1 file changed, 11 insertions(+), 13 deletions(-) - -diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c -index 2d96e30..8551a54 100644 ---- a/arch/x86/kvm/svm.c -+++ b/arch/x86/kvm/svm.c -@@ -1876,6 +1876,7 @@ static void svm_get_segment(struct kvm_vcpu *vcpu, - */ - if (var->unusable) - var->db = 0; -+ /* This is symmetric with svm_set_segment() */ - var->dpl = to_svm(vcpu)->vmcb->save.cpl; - break; - } -@@ -2021,18 +2022,14 @@ static void svm_set_segment(struct kvm_vcpu *vcpu, - s->base = var->base; - s->limit = var->limit; - s->selector = var->selector; -- if (var->unusable) -- s->attrib = 0; -- else { -- s->attrib = (var->type & SVM_SELECTOR_TYPE_MASK); -- s->attrib |= (var->s & 1) << SVM_SELECTOR_S_SHIFT; -- s->attrib |= (var->dpl & 3) << SVM_SELECTOR_DPL_SHIFT; -- s->attrib |= (var->present & 1) << SVM_SELECTOR_P_SHIFT; -- s->attrib |= (var->avl & 1) << SVM_SELECTOR_AVL_SHIFT; -- s->attrib |= (var->l & 1) << SVM_SELECTOR_L_SHIFT; -- s->attrib |= (var->db & 1) << SVM_SELECTOR_DB_SHIFT; -- s->attrib |= (var->g & 1) << SVM_SELECTOR_G_SHIFT; -- } -+ s->attrib = (var->type & SVM_SELECTOR_TYPE_MASK); -+ s->attrib |= (var->s & 1) << SVM_SELECTOR_S_SHIFT; -+ s->attrib |= (var->dpl & 3) << SVM_SELECTOR_DPL_SHIFT; -+ s->attrib |= ((var->present & 1) && !var->unusable) << SVM_SELECTOR_P_SHIFT; -+ s->attrib |= (var->avl & 1) << SVM_SELECTOR_AVL_SHIFT; -+ s->attrib |= (var->l & 1) << SVM_SELECTOR_L_SHIFT; -+ s->attrib |= (var->db & 1) << SVM_SELECTOR_DB_SHIFT; -+ s->attrib |= (var->g & 1) << SVM_SELECTOR_G_SHIFT; - - /* - * This is always accurate, except if SYSRET returned to a segment -@@ -2041,7 +2038,8 @@ static void svm_set_segment(struct kvm_vcpu *vcpu, - * would entail passing the CPL to userspace and back. - */ - if (seg == VCPU_SREG_SS) -- svm->vmcb->save.cpl = (s->attrib >> SVM_SELECTOR_DPL_SHIFT) & 3; -+ /* This is symmetric with svm_get_segment() */ -+ svm->vmcb->save.cpl = (var->dpl & 3); - - mark_dirty(svm->vmcb, VMCB_SEG); - } --- -2.7.4 - |