abb023fb95
XSAVE-enabled features like AVX. - Store a per-cpu guest xcr0 register. When switching to the guest FPU state, switch to the guest xcr0 value. Note that the guest FPU state is saved and restored using the host's xcr0 value and xcr0 is saved/restored "inside" of saving/restoring the guest FPU state. - Handle VM exits for the xsetbv instruction by updating the guest xcr0. - Expose the XSAVE feature to the guest only if the host has enabled XSAVE, and only advertise XSAVE features enabled by the host to the guest. This ensures that the guest will only adjust FPU state that is a subset of the guest FPU state saved and restored by the host. Reviewed by: grehan
157 lines
3.3 KiB
C
157 lines
3.3 KiB
C
/*-
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* Copyright (c) 2012 NetApp, Inc.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY NETAPP, INC ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL NETAPP, INC OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/pcpu.h>
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#include <machine/cpufunc.h>
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#include <machine/segments.h>
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#include <machine/specialreg.h>
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#include "vmm_host.h"
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static uint64_t vmm_host_efer, vmm_host_pat, vmm_host_cr0, vmm_host_cr4,
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vmm_host_xcr0;
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static struct xsave_limits vmm_xsave_limits;
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void
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vmm_host_state_init(void)
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{
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int regs[4];
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vmm_host_efer = rdmsr(MSR_EFER);
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vmm_host_pat = rdmsr(MSR_PAT);
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/*
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* We always want CR0.TS to be set when the processor does a VM exit.
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*
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* With emulation turned on unconditionally after a VM exit, we are
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* able to trap inadvertent use of the FPU until the guest FPU state
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* has been safely squirreled away.
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*/
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vmm_host_cr0 = rcr0() | CR0_TS;
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vmm_host_cr4 = rcr4();
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/*
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* Only permit a guest to use XSAVE if the host is using
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* XSAVE. Only permit a guest to use XSAVE features supported
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* by the host. This ensures that the FPU state used by the
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* guest is always a subset of the saved guest FPU state.
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*/
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if (vmm_host_cr4 & CR4_XSAVE) {
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vmm_xsave_limits.xsave_enabled = 1;
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vmm_host_xcr0 = rxcr(0);
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vmm_xsave_limits.xcr0_allowed = vmm_host_xcr0;
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cpuid_count(0xd, 0x0, regs);
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vmm_xsave_limits.xsave_max_size = regs[1];
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}
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}
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uint64_t
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vmm_get_host_pat(void)
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{
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return (vmm_host_pat);
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}
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uint64_t
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vmm_get_host_efer(void)
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{
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return (vmm_host_efer);
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}
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uint64_t
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vmm_get_host_cr0(void)
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{
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return (vmm_host_cr0);
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}
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uint64_t
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vmm_get_host_cr4(void)
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{
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return (vmm_host_cr4);
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}
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uint64_t
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vmm_get_host_xcr0(void)
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{
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return (vmm_host_xcr0);
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}
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uint64_t
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vmm_get_host_datasel(void)
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{
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return (GSEL(GDATA_SEL, SEL_KPL));
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}
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uint64_t
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vmm_get_host_codesel(void)
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{
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return (GSEL(GCODE_SEL, SEL_KPL));
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}
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uint64_t
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vmm_get_host_tsssel(void)
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{
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return (GSEL(GPROC0_SEL, SEL_KPL));
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}
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uint64_t
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vmm_get_host_fsbase(void)
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{
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return (0);
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}
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uint64_t
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vmm_get_host_idtrbase(void)
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{
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return (r_idt.rd_base);
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}
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const struct xsave_limits *
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vmm_get_xsave_limits(void)
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{
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return (&vmm_xsave_limits);
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}
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