• Sean Christopherson's avatar
    KVM: x86: Introduce KVM_REQ_TLB_FLUSH_CURRENT to flush current ASID · eeeb4f67
    Sean Christopherson authored
    Add KVM_REQ_TLB_FLUSH_CURRENT to allow optimized TLB flushing of VMX's
    EPTP/VPID contexts[*] from the KVM MMU and/or in a deferred manner, e.g.
    to flush L2's context during nested VM-Enter.
    
    Convert KVM_REQ_TLB_FLUSH to KVM_REQ_TLB_FLUSH_CURRENT in flows where
    the flush is directly associated with vCPU-scoped instruction emulation,
    i.e. MOV CR3 and INVPCID.
    
    Add a comment in vmx_vcpu_load_vmcs() above its KVM_REQ_TLB_FLUSH to
    make it clear that it deliberately requests a flush of all contexts.
    
    Service any pending flush request on nested VM-Exit as it's possible a
    nested VM-Exit could occur after requesting a flush for L2.  Add the
    same logic for nested VM-Enter even though it's _extremely_ unlikely
    for flush to be pending on nested VM-Enter, but theoretically possible
    (in the future) due to RSM (SMM) emulation.
    
    [*] Intel also has an Address Space Identifier (ASID) concept, e.g.
        EPTP+VPID+PCID == ASID, it's just not documented in the SDM because
        the rules of invalidation are different based on which piece of the
        ASID is being changed, i.e. whether the EPTP, VPID, or PCID context
        must be invalidated.
    Signed-off-by: default avatarSean Christopherson <sean.j.christopherson@intel.com>
    Message-Id: <20200320212833.3507-25-sean.j.christopherson@intel.com>
    Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
    eeeb4f67
nested.c 193 KB