diff options
| author | Paolo Bonzini <pbonzini@redhat.com> | 2018-07-02 13:07:14 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-08-15 18:14:48 +0200 |
| commit | b3dc63c4f43e57d73d769ad0d3f34eae74cb68a8 (patch) | |
| tree | 9f8680294f6cb43985c0038a021a477f81f9d256 /arch/x86/kvm/x86.c | |
| parent | acca8a70a5f6179007e1148a62b8bef12b212d9b (diff) | |
x86/KVM/VMX: Add L1D flush logic
commit c595ceee45707f00f64f61c54fb64ef0cc0b4e85 upstream
Add the logic for flushing L1D on VMENTER. The flush depends on the static
key being enabled and the new l1tf_flush_l1d flag being set.
The flags is set:
- Always, if the flush module parameter is 'always'
- Conditionally at:
- Entry to vcpu_run(), i.e. after executing user space
- From the sched_in notifier, i.e. when switching to a vCPU thread.
- From vmexit handlers which are considered unsafe, i.e. where
sensitive data can be brought into L1D:
- The emulator, which could be a good target for other speculative
execution-based threats,
- The MMU, which can bring host page tables in the L1 cache.
- External interrupts
- Nested operations that require the MMU (see above). That is
vmptrld, vmptrst, vmclear,vmwrite,vmread.
- When handling invept,invvpid
[ tglx: Split out from combo patch and reduced to a single flag ]
[ dwmw2: Backported to 4.9, set l1tf_flush_l1d in svm/vmx code ]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/x86/kvm/x86.c')
| -rw-r--r-- | arch/x86/kvm/x86.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 5ca23af44c81..cc314e787e85 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -180,6 +180,7 @@ struct kvm_stats_debugfs_item debugfs_entries[] = { { "insn_emulation_fail", VCPU_STAT(insn_emulation_fail) }, { "irq_injections", VCPU_STAT(irq_injections) }, { "nmi_injections", VCPU_STAT(nmi_injections) }, + { "l1d_flush", VCPU_STAT(l1d_flush) }, { "mmu_shadow_zapped", VM_STAT(mmu_shadow_zapped) }, { "mmu_pte_write", VM_STAT(mmu_pte_write) }, { "mmu_pte_updated", VM_STAT(mmu_pte_updated) }, @@ -4476,6 +4477,9 @@ static int emulator_write_std(struct x86_emulate_ctxt *ctxt, gva_t addr, void *v int kvm_write_guest_virt_system(struct kvm_vcpu *vcpu, gva_t addr, void *val, unsigned int bytes, struct x86_exception *exception) { + /* kvm_write_guest_virt_system can pull in tons of pages. */ + vcpu->arch.l1tf_flush_l1d = true; + return kvm_write_guest_virt_helper(addr, val, bytes, vcpu, PFERR_WRITE_MASK, exception); } @@ -5574,6 +5578,8 @@ int x86_emulate_instruction(struct kvm_vcpu *vcpu, bool writeback = true; bool write_fault_to_spt = vcpu->arch.write_fault_to_shadow_pgtable; + vcpu->arch.l1tf_flush_l1d = true; + /* * Clear write_fault_to_shadow_pgtable here to ensure it is * never reused. @@ -6929,6 +6935,7 @@ static int vcpu_run(struct kvm_vcpu *vcpu) struct kvm *kvm = vcpu->kvm; vcpu->srcu_idx = srcu_read_lock(&kvm->srcu); + vcpu->arch.l1tf_flush_l1d = true; for (;;) { if (kvm_vcpu_running(vcpu)) { @@ -7899,6 +7906,7 @@ void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu) void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) { + vcpu->arch.l1tf_flush_l1d = true; kvm_x86_ops->sched_in(vcpu, cpu); } |