e3d386d9fe
guest for which the rules regarding xsetbv emulation are known. In particular future extensions like AVX-512 have interdependencies among feature bits that could allow a guest to trigger a GP# in the host with the current approach of allowing anything the host supports. - Add proper checking of Intel MPX and AVX-512 XSAVE features in the xsetbv emulation and allow these features to be exposed to the guest if they are enabled in the host. - Expose a subset of known-safe features from leaf 0 of the structured extended features to guests if they are supported on the host including RDFSBASE/RDGSBASE, BMI1/2, AVX2, AVX-512, HLE, ERMS, and RTM. Aside from AVX-512, these features are all new instructions available for use in ring 3 with no additional hypervisor changes needed. Reviewed by: neel
162 lines
3.5 KiB
C
162 lines
3.5 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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* In addition, only permit known XSAVE features where the
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* rules for which features depend on other features is known
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* to properly emulate xsetbv.
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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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(XFEATURE_AVX | XFEATURE_MPX | XFEATURE_AVX512);
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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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