diff options
Diffstat (limited to 'common/recipes-kernel/linux/linux-yocto-4.9.21/0013-x86-kvm-Update-spectre-v1-mitigation.patch')
| -rw-r--r-- | common/recipes-kernel/linux/linux-yocto-4.9.21/0013-x86-kvm-Update-spectre-v1-mitigation.patch | 72 |
1 files changed, 72 insertions, 0 deletions
diff --git a/common/recipes-kernel/linux/linux-yocto-4.9.21/0013-x86-kvm-Update-spectre-v1-mitigation.patch b/common/recipes-kernel/linux/linux-yocto-4.9.21/0013-x86-kvm-Update-spectre-v1-mitigation.patch new file mode 100644 index 00000000..8b58f32e --- /dev/null +++ b/common/recipes-kernel/linux/linux-yocto-4.9.21/0013-x86-kvm-Update-spectre-v1-mitigation.patch @@ -0,0 +1,72 @@ +From 7a1d0c7758b49b1f107157db33df0aae1c10cf26 Mon Sep 17 00:00:00 2001 +From: Dan Williams <dan.j.williams@intel.com> +Date: Wed, 31 Jan 2018 17:47:03 -0800 +Subject: [PATCH 13/33] x86/kvm: Update spectre-v1 mitigation + +(cherry picked from commit 085331dfc6bbe3501fb936e657331ca943827600) + +Commit 75f139aaf896 "KVM: x86: Add memory barrier on vmcs field lookup" +added a raw 'asm("lfence");' to prevent a bounds check bypass of +'vmcs_field_to_offset_table'. + +The lfence can be avoided in this path by using the array_index_nospec() +helper designed for these types of fixes. + +Signed-off-by: Dan Williams <dan.j.williams@intel.com> +Signed-off-by: Thomas Gleixner <tglx@linutronix.de> +Acked-by: Paolo Bonzini <pbonzini@redhat.com> +Cc: Andrew Honig <ahonig@google.com> +Cc: kvm@vger.kernel.org +Cc: Jim Mattson <jmattson@google.com> +Link: https://lkml.kernel.org/r/151744959670.6342.3001723920950249067.stgit@dwillia2-desk3.amr.corp.intel.com +Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> +Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> +--- + arch/x86/kvm/vmx.c | 20 +++++++++----------- + 1 file changed, 9 insertions(+), 11 deletions(-) + +diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c +index 6f3ed0e..af90bc4 100644 +--- a/arch/x86/kvm/vmx.c ++++ b/arch/x86/kvm/vmx.c +@@ -33,6 +33,7 @@ + #include <linux/slab.h> + #include <linux/tboot.h> + #include <linux/hrtimer.h> ++#include <linux/nospec.h> + #include "kvm_cache_regs.h" + #include "x86.h" + +@@ -856,21 +857,18 @@ static const unsigned short vmcs_field_to_offset_table[] = { + + static inline short vmcs_field_to_offset(unsigned long field) + { +- BUILD_BUG_ON(ARRAY_SIZE(vmcs_field_to_offset_table) > SHRT_MAX); ++ const size_t size = ARRAY_SIZE(vmcs_field_to_offset_table); ++ unsigned short offset; + +- if (field >= ARRAY_SIZE(vmcs_field_to_offset_table)) ++ BUILD_BUG_ON(size > SHRT_MAX); ++ if (field >= size) + return -ENOENT; + +- /* +- * FIXME: Mitigation for CVE-2017-5753. To be replaced with a +- * generic mechanism. +- */ +- asm("lfence"); +- +- if (vmcs_field_to_offset_table[field] == 0) ++ field = array_index_nospec(field, size); ++ offset = vmcs_field_to_offset_table[field]; ++ if (offset == 0) + return -ENOENT; +- +- return vmcs_field_to_offset_table[field]; ++ return offset; + } + + static inline struct vmcs12 *get_vmcs12(struct kvm_vcpu *vcpu) +-- +2.7.4 + |