44a68c4e40
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
369 lines
8.8 KiB
C
369 lines
8.8 KiB
C
/*-
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* Copyright (c) 2011 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 <sys/systm.h>
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#include <sys/cpuset.h>
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#include <machine/clock.h>
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#include <machine/cpufunc.h>
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#include <machine/md_var.h>
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#include <machine/segments.h>
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#include <machine/specialreg.h>
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#include <machine/vmm.h>
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#include "vmm_host.h"
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#include "x86.h"
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#define CPUID_VM_HIGH 0x40000000
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static const char bhyve_id[12] = "bhyve bhyve ";
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static uint64_t bhyve_xcpuids;
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int
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x86_emulate_cpuid(struct vm *vm, int vcpu_id,
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uint32_t *eax, uint32_t *ebx, uint32_t *ecx, uint32_t *edx)
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{
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const struct xsave_limits *limits;
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uint64_t cr4;
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int error, enable_invpcid;
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unsigned int func, regs[4];
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enum x2apic_state x2apic_state;
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/*
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* Requests for invalid CPUID levels should map to the highest
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* available level instead.
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*/
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if (cpu_exthigh != 0 && *eax >= 0x80000000) {
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if (*eax > cpu_exthigh)
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*eax = cpu_exthigh;
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} else if (*eax >= 0x40000000) {
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if (*eax > CPUID_VM_HIGH)
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*eax = CPUID_VM_HIGH;
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} else if (*eax > cpu_high) {
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*eax = cpu_high;
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}
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func = *eax;
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/*
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* In general the approach used for CPU topology is to
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* advertise a flat topology where all CPUs are packages with
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* no multi-core or SMT.
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*/
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switch (func) {
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/*
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* Pass these through to the guest
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*/
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case CPUID_0000_0000:
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case CPUID_0000_0002:
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case CPUID_0000_0003:
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case CPUID_8000_0000:
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case CPUID_8000_0002:
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case CPUID_8000_0003:
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case CPUID_8000_0004:
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case CPUID_8000_0006:
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case CPUID_8000_0008:
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cpuid_count(*eax, *ecx, regs);
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break;
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case CPUID_8000_0001:
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/*
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* Hide rdtscp/ia32_tsc_aux until we know how
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* to deal with them.
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*/
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cpuid_count(*eax, *ecx, regs);
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regs[3] &= ~AMDID_RDTSCP;
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break;
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case CPUID_8000_0007:
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cpuid_count(*eax, *ecx, regs);
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/*
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* If the host TSCs are not synchronized across
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* physical cpus then we cannot advertise an
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* invariant tsc to a vcpu.
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*
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* XXX This still falls short because the vcpu
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* can observe the TSC moving backwards as it
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* migrates across physical cpus. But at least
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* it should discourage the guest from using the
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* TSC to keep track of time.
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*/
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if (!smp_tsc)
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regs[3] &= ~AMDPM_TSC_INVARIANT;
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break;
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case CPUID_0000_0001:
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do_cpuid(1, regs);
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error = vm_get_x2apic_state(vm, vcpu_id, &x2apic_state);
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if (error) {
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panic("x86_emulate_cpuid: error %d "
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"fetching x2apic state", error);
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}
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/*
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* Override the APIC ID only in ebx
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*/
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regs[1] &= ~(CPUID_LOCAL_APIC_ID);
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regs[1] |= (vcpu_id << CPUID_0000_0001_APICID_SHIFT);
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/*
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* Don't expose VMX, SpeedStep or TME capability.
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* Advertise x2APIC capability and Hypervisor guest.
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*/
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regs[2] &= ~(CPUID2_VMX | CPUID2_EST | CPUID2_TM2);
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regs[2] |= CPUID2_HV;
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if (x2apic_state != X2APIC_DISABLED)
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regs[2] |= CPUID2_X2APIC;
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else
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regs[2] &= ~CPUID2_X2APIC;
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/*
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* Only advertise CPUID2_XSAVE in the guest if
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* the host is using XSAVE.
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*/
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if (!(regs[2] & CPUID2_OSXSAVE))
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regs[2] &= ~CPUID2_XSAVE;
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/*
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* If CPUID2_XSAVE is being advertised and the
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* guest has set CR4_XSAVE, set
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* CPUID2_OSXSAVE.
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*/
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regs[2] &= ~CPUID2_OSXSAVE;
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if (regs[2] & CPUID2_XSAVE) {
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error = vm_get_register(vm, vcpu_id,
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VM_REG_GUEST_CR4, &cr4);
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if (error)
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panic("x86_emulate_cpuid: error %d "
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"fetching %%cr4", error);
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if (cr4 & CR4_XSAVE)
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regs[2] |= CPUID2_OSXSAVE;
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}
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/*
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* Hide monitor/mwait until we know how to deal with
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* these instructions.
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*/
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regs[2] &= ~CPUID2_MON;
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/*
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* Hide the performance and debug features.
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*/
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regs[2] &= ~CPUID2_PDCM;
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/*
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* No TSC deadline support in the APIC yet
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*/
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regs[2] &= ~CPUID2_TSCDLT;
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/*
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* Hide thermal monitoring
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*/
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regs[3] &= ~(CPUID_ACPI | CPUID_TM);
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/*
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* Machine check handling is done in the host.
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* Hide MTRR capability.
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*/
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regs[3] &= ~(CPUID_MCA | CPUID_MCE | CPUID_MTRR);
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/*
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* Hide the debug store capability.
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*/
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regs[3] &= ~CPUID_DS;
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/*
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* Disable multi-core.
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*/
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regs[1] &= ~CPUID_HTT_CORES;
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regs[3] &= ~CPUID_HTT;
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break;
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case CPUID_0000_0004:
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do_cpuid(4, regs);
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/*
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* Do not expose topology.
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*
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* The maximum number of processor cores in
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* this physical processor package and the
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* maximum number of threads sharing this
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* cache are encoded with "plus 1" encoding.
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* Adding one to the value in this register
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* field to obtains the actual value.
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*
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* Therefore 0 for both indicates 1 core per
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* package and no cache sharing.
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*/
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regs[0] &= 0xffff8000;
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break;
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case CPUID_0000_0007:
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regs[0] = 0;
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regs[1] = 0;
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regs[2] = 0;
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regs[3] = 0;
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/* leaf 0 */
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if (*ecx == 0) {
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cpuid_count(*eax, *ecx, regs);
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/* Only leaf 0 is supported */
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regs[0] = 0;
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/*
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* Expose known-safe features.
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*/
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regs[1] &= (CPUID_STDEXT_FSGSBASE |
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CPUID_STDEXT_BMI1 | CPUID_STDEXT_HLE |
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CPUID_STDEXT_AVX2 | CPUID_STDEXT_BMI2 |
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CPUID_STDEXT_ERMS | CPUID_STDEXT_RTM |
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CPUID_STDEXT_AVX512F |
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CPUID_STDEXT_AVX512PF |
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CPUID_STDEXT_AVX512ER |
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CPUID_STDEXT_AVX512CD);
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regs[2] = 0;
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regs[3] = 0;
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/* Advertise INVPCID if it is enabled. */
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error = vm_get_capability(vm, vcpu_id,
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VM_CAP_ENABLE_INVPCID, &enable_invpcid);
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if (error == 0 && enable_invpcid)
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regs[1] |= CPUID_STDEXT_INVPCID;
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}
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break;
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case CPUID_0000_0006:
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case CPUID_0000_000A:
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/*
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* Handle the access, but report 0 for
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* all options
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*/
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regs[0] = 0;
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regs[1] = 0;
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regs[2] = 0;
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regs[3] = 0;
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break;
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case CPUID_0000_000B:
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/*
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* Processor topology enumeration
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*/
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regs[0] = 0;
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regs[1] = 0;
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regs[2] = *ecx & 0xff;
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regs[3] = vcpu_id;
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break;
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case CPUID_0000_000D:
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limits = vmm_get_xsave_limits();
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if (!limits->xsave_enabled) {
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regs[0] = 0;
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regs[1] = 0;
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regs[2] = 0;
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regs[3] = 0;
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break;
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}
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cpuid_count(*eax, *ecx, regs);
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switch (*ecx) {
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case 0:
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/*
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* Only permit the guest to use bits
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* that are active in the host in
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* %xcr0. Also, claim that the
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* maximum save area size is
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* equivalent to the host's current
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* save area size. Since this runs
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* "inside" of vmrun(), it runs with
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* the guest's xcr0, so the current
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* save area size is correct as-is.
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*/
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regs[0] &= limits->xcr0_allowed;
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regs[2] = limits->xsave_max_size;
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regs[3] &= (limits->xcr0_allowed >> 32);
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break;
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case 1:
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/* Only permit XSAVEOPT. */
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regs[0] &= CPUID_EXTSTATE_XSAVEOPT;
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regs[1] = 0;
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regs[2] = 0;
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regs[3] = 0;
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break;
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default:
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/*
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* If the leaf is for a permitted feature,
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* pass through as-is, otherwise return
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* all zeroes.
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*/
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if (!(limits->xcr0_allowed & (1ul << *ecx))) {
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regs[0] = 0;
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regs[1] = 0;
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regs[2] = 0;
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regs[3] = 0;
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}
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break;
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}
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break;
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case 0x40000000:
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regs[0] = CPUID_VM_HIGH;
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bcopy(bhyve_id, ®s[1], 4);
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bcopy(bhyve_id + 4, ®s[2], 4);
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bcopy(bhyve_id + 8, ®s[3], 4);
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break;
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default:
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/*
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* The leaf value has already been clamped so
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* simply pass this through, keeping count of
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* how many unhandled leaf values have been seen.
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*/
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atomic_add_long(&bhyve_xcpuids, 1);
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cpuid_count(*eax, *ecx, regs);
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break;
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}
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*eax = regs[0];
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*ebx = regs[1];
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*ecx = regs[2];
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*edx = regs[3];
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return (1);
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}
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