FreeBSD/Linux Kernel Cross Reference
sys/amd64/vmm/vmm_host.c

     /*-
      * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
      *
      * Copyright (c) 2012 NetApp, Inc.
      * All rights reserved.
      *
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
      * are met:
     * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     *
     * THIS SOFTWARE IS PROVIDED BY NETAPP, INC ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL NETAPP, INC OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     *
     * $FreeBSD$
     */
    
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD$");
    
    #include <sys/param.h>
    #include <sys/pcpu.h>
    
    #include <machine/cpufunc.h>
    #include <machine/segments.h>
    #include <machine/specialreg.h>
    
    #include "vmm_host.h"
    
    static uint64_t vmm_host_efer, vmm_host_pat, vmm_host_cr0, vmm_host_cr4,
            vmm_host_xcr0;
    static struct xsave_limits vmm_xsave_limits;
    
    void
    vmm_host_state_init(void)
    {
            int regs[4];
    
            vmm_host_efer = rdmsr(MSR_EFER);
            vmm_host_pat = rdmsr(MSR_PAT);
    
            /*
             * We always want CR0.TS to be set when the processor does a VM exit.
             *
             * With emulation turned on unconditionally after a VM exit, we are
             * able to trap inadvertent use of the FPU until the guest FPU state
             * has been safely squirreled away.
             */
            vmm_host_cr0 = rcr0() | CR0_TS;
    
            /*
             * On non-PCID or PCID but without INVPCID support machines,
             * we flush kernel i.e. global TLB entries, by temporary
             * clearing the CR4.PGE bit, see invltlb_glob().  If
             * preemption occurs at the wrong time, cached vmm_host_cr4
             * might store the value with CR4.PGE cleared.  Since FreeBSD
             * requires support for PG_G on amd64, just set it
             * unconditionally.
             */
            vmm_host_cr4 = rcr4() | CR4_PGE;
    
            /*
             * Only permit a guest to use XSAVE if the host is using
             * XSAVE.  Only permit a guest to use XSAVE features supported
             * by the host.  This ensures that the FPU state used by the
             * guest is always a subset of the saved guest FPU state.
             *
             * In addition, only permit known XSAVE features where the
             * rules for which features depend on other features is known
             * to properly emulate xsetbv.
             */
            if (vmm_host_cr4 & CR4_XSAVE) {
                    vmm_xsave_limits.xsave_enabled = 1;
                    vmm_host_xcr0 = rxcr(0);
                    vmm_xsave_limits.xcr0_allowed = vmm_host_xcr0 &
                        (XFEATURE_AVX | XFEATURE_MPX | XFEATURE_AVX512);
    
                    cpuid_count(0xd, 0x0, regs);
                    vmm_xsave_limits.xsave_max_size = regs[1];
            }
    }
    
    uint64_t
    vmm_get_host_pat(void)
    {
    
           return (vmm_host_pat);
   }
   
   uint64_t
   vmm_get_host_efer(void)
   {
   
           return (vmm_host_efer);
   }
   
   uint64_t
   vmm_get_host_cr0(void)
   {
   
           return (vmm_host_cr0);
   }
   
   uint64_t
   vmm_get_host_cr4(void)
   {
   
           return (vmm_host_cr4);
   }
   
   uint64_t
   vmm_get_host_xcr0(void)
   {
   
           return (vmm_host_xcr0);
   }
   
   uint64_t
   vmm_get_host_datasel(void)
   {
   
           return (GSEL(GDATA_SEL, SEL_KPL));
   
   }
   
   uint64_t
   vmm_get_host_codesel(void)
   {
   
           return (GSEL(GCODE_SEL, SEL_KPL));
   }
   
   uint64_t
   vmm_get_host_tsssel(void)
   {
   
           return (GSEL(GPROC0_SEL, SEL_KPL));
   }
   
   uint64_t
   vmm_get_host_fsbase(void)
   {
   
           return (0);
   }
   
   uint64_t
   vmm_get_host_idtrbase(void)
   {
   
           return (r_idt.rd_base);
   }
   
   const struct xsave_limits *
   vmm_get_xsave_limits(void)
   {
   
           return (&vmm_xsave_limits);
   }

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