3.16.84-rc1 review patch. If anyone has any objections, please let me know.
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From: Marios Pomonis pomonis@google.com
commit 4bf79cb089f6b1c6c632492c0271054ce52ad766 upstream.
This fixes a Spectre-v1/L1TF vulnerability in kvm_lapic_reg_write(). This function contains index computations based on the (attacker-controlled) MSR number.
Fixes: 0105d1a52640 ("KVM: x2apic interface to lapic")
Signed-off-by: Nick Finco nifi@google.com Signed-off-by: Marios Pomonis pomonis@google.com Reviewed-by: Andrew Honig ahonig@google.com Reviewed-by: Jim Mattson jmattson@google.com Signed-off-by: Paolo Bonzini pbonzini@redhat.com [bwh: Backported to 3.16: - Add #include <linux/nospec.h> - Adjust context] Signed-off-by: Ben Hutchings ben@decadent.org.uk --- --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -35,6 +35,7 @@ #include <asm/apicdef.h> #include <linux/atomic.h> #include <linux/jump_label.h> +#include <linux/nospec.h> #include "kvm_cache_regs.h" #include "irq.h" #include "trace.h" @@ -1196,15 +1197,20 @@ static int apic_reg_write(struct kvm_lap case APIC_LVTTHMR: case APIC_LVTPC: case APIC_LVT1: - case APIC_LVTERR: + case APIC_LVTERR: { /* TODO: Check vector */ + size_t size; + u32 index; + if (!kvm_apic_sw_enabled(apic)) val |= APIC_LVT_MASKED; - - val &= apic_lvt_mask[(reg - APIC_LVTT) >> 4]; + size = ARRAY_SIZE(apic_lvt_mask); + index = array_index_nospec( + (reg - APIC_LVTT) >> 4, size); + val &= apic_lvt_mask[index]; apic_set_reg(apic, reg, val); - break; + }
case APIC_LVTT: if ((kvm_apic_get_reg(apic, APIC_LVTT) &