freebsd-skq/sys/amd64/vmm/vmm_host.c
kib dd08c073d0 Correct undesirable interaction between caching of %cr4 in bhyve and
invltlb_glob().

Reviewed by:	grehan, jhb
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
Differential revision:	https://reviews.freebsd.org/D15138
2018-04-24 13:44:19 +00:00

173 lines
3.9 KiB
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);
}