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freebsd-skq/sys/amd64/vmm/amd/vmcb.h
jhb d3e4e51223 Initial support for bhyve save and restore. 
Save and restore (also known as suspend and resume) permits a snapshot
to be taken of a guest's state that can later be resumed.  In the
current implementation, bhyve(8) creates a UNIX domain socket that is
used by bhyvectl(8) to send a request to save a snapshot (and
optionally exit after the snapshot has been taken).  A snapshot
currently consists of two files: the first holds a copy of guest RAM,
and the second file holds other guest state such as vCPU register
values and device model state.

To resume a guest, bhyve(8) must be started with a matching pair of
command line arguments to instantiate the same set of device models as
well as a pointer to the saved snapshot.

While the current implementation is useful for several uses cases, it
has a few limitations.  The file format for saving the guest state is
tied to the ABI of internal bhyve structures and is not
self-describing (in that it does not communicate the set of device
models present in the system).  In addition, the state saved for some
device models closely matches the internal data structures which might
prove a challenge for compatibility of snapshot files across a range
of bhyve versions.  The file format also does not currently support
versioning of individual chunks of state.  As a result, the current
file format is not a fixed binary format and future revisions to save
and restore will break binary compatiblity of snapshot files.  The
goal is to move to a more flexible format that adds versioning,
etc. and at that point to commit to providing a reasonable level of
compatibility.  As a result, the current implementation is not enabled
by default.  It can be enabled via the WITH_BHYVE_SNAPSHOT=yes option
for userland builds, and the kernel option BHYVE_SHAPSHOT.

Submitted by:	Mihai Tiganus, Flavius Anton, Darius Mihai
Submitted by:	Elena Mihailescu, Mihai Carabas, Sergiu Weisz
Relnotes:	yes
Sponsored by:	University Politehnica of Bucharest
Sponsored by:	Matthew Grooms (student scholarships)
Sponsored by:	iXsystems
Differential Revision:	https://reviews.freebsd.org/D19495
2020-05-05 00:02:04 +00:00

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/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2013 Anish Gupta (akgupt3@gmail.com)
* 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 unmodified, 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 THE AUTHOR ``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 THE AUTHOR 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.
*
* $FreeBSD$
*/
#ifndef _VMCB_H_
#define _VMCB_H_
#define BIT(n) (1ULL << n)
/*
* Secure Virtual Machine: AMD64 Programmer's Manual Vol2, Chapter 15
* Layout of VMCB: AMD64 Programmer's Manual Vol2, Appendix B
*/
/* vmcb_ctrl->intercept[] array indices */
#define VMCB_CR_INTCPT 0
#define VMCB_DR_INTCPT 1
#define VMCB_EXC_INTCPT 2
#define VMCB_CTRL1_INTCPT 3
#define VMCB_CTRL2_INTCPT 4
/* intercept[VMCB_CTRL1_INTCPT] fields */
#define VMCB_INTCPT_INTR BIT(0)
#define VMCB_INTCPT_NMI BIT(1)
#define VMCB_INTCPT_SMI BIT(2)
#define VMCB_INTCPT_INIT BIT(3)
#define VMCB_INTCPT_VINTR BIT(4)
#define VMCB_INTCPT_CR0_WRITE BIT(5)
#define VMCB_INTCPT_IDTR_READ BIT(6)
#define VMCB_INTCPT_GDTR_READ BIT(7)
#define VMCB_INTCPT_LDTR_READ BIT(8)
#define VMCB_INTCPT_TR_READ BIT(9)
#define VMCB_INTCPT_IDTR_WRITE BIT(10)
#define VMCB_INTCPT_GDTR_WRITE BIT(11)
#define VMCB_INTCPT_LDTR_WRITE BIT(12)
#define VMCB_INTCPT_TR_WRITE BIT(13)
#define VMCB_INTCPT_RDTSC BIT(14)
#define VMCB_INTCPT_RDPMC BIT(15)
#define VMCB_INTCPT_PUSHF BIT(16)
#define VMCB_INTCPT_POPF BIT(17)
#define VMCB_INTCPT_CPUID BIT(18)
#define VMCB_INTCPT_RSM BIT(19)
#define VMCB_INTCPT_IRET BIT(20)
#define VMCB_INTCPT_INTn BIT(21)
#define VMCB_INTCPT_INVD BIT(22)
#define VMCB_INTCPT_PAUSE BIT(23)
#define VMCB_INTCPT_HLT BIT(24)
#define VMCB_INTCPT_INVPG BIT(25)
#define VMCB_INTCPT_INVPGA BIT(26)
#define VMCB_INTCPT_IO BIT(27)
#define VMCB_INTCPT_MSR BIT(28)
#define VMCB_INTCPT_TASK_SWITCH BIT(29)
#define VMCB_INTCPT_FERR_FREEZE BIT(30)
#define VMCB_INTCPT_SHUTDOWN BIT(31)
/* intercept[VMCB_CTRL2_INTCPT] fields */
#define VMCB_INTCPT_VMRUN BIT(0)
#define VMCB_INTCPT_VMMCALL BIT(1)
#define VMCB_INTCPT_VMLOAD BIT(2)
#define VMCB_INTCPT_VMSAVE BIT(3)
#define VMCB_INTCPT_STGI BIT(4)
#define VMCB_INTCPT_CLGI BIT(5)
#define VMCB_INTCPT_SKINIT BIT(6)
#define VMCB_INTCPT_RDTSCP BIT(7)
#define VMCB_INTCPT_ICEBP BIT(8)
#define VMCB_INTCPT_WBINVD BIT(9)
#define VMCB_INTCPT_MONITOR BIT(10)
#define VMCB_INTCPT_MWAIT BIT(11)
#define VMCB_INTCPT_MWAIT_ARMED BIT(12)
#define VMCB_INTCPT_XSETBV BIT(13)
/* VMCB TLB control */
#define VMCB_TLB_FLUSH_NOTHING 0 /* Flush nothing */
#define VMCB_TLB_FLUSH_ALL 1 /* Flush entire TLB */
#define VMCB_TLB_FLUSH_GUEST 3 /* Flush all guest entries */
#define VMCB_TLB_FLUSH_GUEST_NONGLOBAL 7 /* Flush guest non-PG entries */
/* VMCB state caching */
#define VMCB_CACHE_NONE 0 /* No caching */
#define VMCB_CACHE_I BIT(0) /* Intercept, TSC off, Pause filter */
#define VMCB_CACHE_IOPM BIT(1) /* I/O and MSR permission */
#define VMCB_CACHE_ASID BIT(2) /* ASID */
#define VMCB_CACHE_TPR BIT(3) /* V_TPR to V_INTR_VECTOR */
#define VMCB_CACHE_NP BIT(4) /* Nested Paging */
#define VMCB_CACHE_CR BIT(5) /* CR0, CR3, CR4 & EFER */
#define VMCB_CACHE_DR BIT(6) /* Debug registers */
#define VMCB_CACHE_DT BIT(7) /* GDT/IDT */
#define VMCB_CACHE_SEG BIT(8) /* User segments, CPL */
#define VMCB_CACHE_CR2 BIT(9) /* page fault address */
#define VMCB_CACHE_LBR BIT(10) /* Last branch */
/* VMCB control event injection */
#define VMCB_EVENTINJ_EC_VALID BIT(11) /* Error Code valid */
#define VMCB_EVENTINJ_VALID BIT(31) /* Event valid */
/* Event types that can be injected */
#define VMCB_EVENTINJ_TYPE_INTR 0
#define VMCB_EVENTINJ_TYPE_NMI 2
#define VMCB_EVENTINJ_TYPE_EXCEPTION 3
#define VMCB_EVENTINJ_TYPE_INTn 4
/* VMCB exit code, APM vol2 Appendix C */
#define VMCB_EXIT_MC 0x52
#define VMCB_EXIT_INTR 0x60
#define VMCB_EXIT_NMI 0x61
#define VMCB_EXIT_VINTR 0x64
#define VMCB_EXIT_PUSHF 0x70
#define VMCB_EXIT_POPF 0x71
#define VMCB_EXIT_CPUID 0x72
#define VMCB_EXIT_IRET 0x74
#define VMCB_EXIT_PAUSE 0x77
#define VMCB_EXIT_HLT 0x78
#define VMCB_EXIT_IO 0x7B
#define VMCB_EXIT_MSR 0x7C
#define VMCB_EXIT_SHUTDOWN 0x7F
#define VMCB_EXIT_VMSAVE 0x83
#define VMCB_EXIT_MONITOR 0x8A
#define VMCB_EXIT_MWAIT 0x8B
#define VMCB_EXIT_NPF 0x400
#define VMCB_EXIT_INVALID -1
/*
* Nested page fault.
* Bit definitions to decode EXITINFO1.
*/
#define VMCB_NPF_INFO1_P BIT(0) /* Nested page present. */
#define VMCB_NPF_INFO1_W BIT(1) /* Access was write. */
#define VMCB_NPF_INFO1_U BIT(2) /* Access was user access. */
#define VMCB_NPF_INFO1_RSV BIT(3) /* Reserved bits present. */
#define VMCB_NPF_INFO1_ID BIT(4) /* Code read. */
#define VMCB_NPF_INFO1_GPA BIT(32) /* Guest physical address. */
#define VMCB_NPF_INFO1_GPT BIT(33) /* Guest page table. */
/*
* EXITINTINFO, Interrupt exit info for all intrecepts.
* Section 15.7.2, Intercepts during IDT Interrupt Delivery.
*/
#define VMCB_EXITINTINFO_VECTOR(x) ((x) & 0xFF)
#define VMCB_EXITINTINFO_TYPE(x) (((x) >> 8) & 0x7)
#define VMCB_EXITINTINFO_EC_VALID(x) (((x) & BIT(11)) ? 1 : 0)
#define VMCB_EXITINTINFO_VALID(x) (((x) & BIT(31)) ? 1 : 0)
#define VMCB_EXITINTINFO_EC(x) (((x) >> 32) & 0xFFFFFFFF)
/* Offset of various VMCB fields. */
#define VMCB_OFF_CTRL(x) (x)
#define VMCB_OFF_STATE(x) ((x) + 0x400)
#define VMCB_OFF_CR_INTERCEPT VMCB_OFF_CTRL(0x0)
#define VMCB_OFF_DR_INTERCEPT VMCB_OFF_CTRL(0x4)
#define VMCB_OFF_EXC_INTERCEPT VMCB_OFF_CTRL(0x8)
#define VMCB_OFF_INST1_INTERCEPT VMCB_OFF_CTRL(0xC)
#define VMCB_OFF_INST2_INTERCEPT VMCB_OFF_CTRL(0x10)
#define VMCB_OFF_IO_PERM VMCB_OFF_CTRL(0x40)
#define VMCB_OFF_MSR_PERM VMCB_OFF_CTRL(0x48)
#define VMCB_OFF_TSC_OFFSET VMCB_OFF_CTRL(0x50)
#define VMCB_OFF_ASID VMCB_OFF_CTRL(0x58)
#define VMCB_OFF_TLB_CTRL VMCB_OFF_CTRL(0x5C)
#define VMCB_OFF_VIRQ VMCB_OFF_CTRL(0x60)
#define VMCB_OFF_EXIT_REASON VMCB_OFF_CTRL(0x70)
#define VMCB_OFF_EXITINFO1 VMCB_OFF_CTRL(0x78)
#define VMCB_OFF_EXITINFO2 VMCB_OFF_CTRL(0x80)
#define VMCB_OFF_EXITINTINFO VMCB_OFF_CTRL(0x88)
#define VMCB_OFF_AVIC_BAR VMCB_OFF_CTRL(0x98)
#define VMCB_OFF_NPT_BASE VMCB_OFF_CTRL(0xB0)
#define VMCB_OFF_AVIC_PAGE VMCB_OFF_CTRL(0xE0)
#define VMCB_OFF_AVIC_LT VMCB_OFF_CTRL(0xF0)
#define VMCB_OFF_AVIC_PT VMCB_OFF_CTRL(0xF8)
#define VMCB_OFF_SYSENTER_CS VMCB_OFF_STATE(0x228)
#define VMCB_OFF_SYSENTER_ESP VMCB_OFF_STATE(0x230)
#define VMCB_OFF_SYSENTER_EIP VMCB_OFF_STATE(0x238)
#define VMCB_OFF_GUEST_PAT VMCB_OFF_STATE(0x268)
/*
* Encode the VMCB offset and bytes that we want to read from VMCB.
*/
#define VMCB_ACCESS(o, w) (0x80000000 | (((w) & 0xF) << 16) | \
((o) & 0xFFF))
#define VMCB_ACCESS_OK(v) ((v) & 0x80000000 )
#define VMCB_ACCESS_BYTES(v) (((v) >> 16) & 0xF)
#define VMCB_ACCESS_OFFSET(v) ((v) & 0xFFF)
#ifdef _KERNEL
struct svm_softc;
struct vm_snapshot_meta;
/* VMCB save state area segment format */
struct vmcb_segment {
uint16_t selector;
uint16_t attrib;
uint32_t limit;
uint64_t base;
} __attribute__ ((__packed__));
CTASSERT(sizeof(struct vmcb_segment) == 16);
/* Code segment descriptor attribute in 12 bit format as saved by VMCB. */
#define VMCB_CS_ATTRIB_L BIT(9) /* Long mode. */
#define VMCB_CS_ATTRIB_D BIT(10) /* OPerand size bit. */
/*
* The VMCB is divided into two areas - the first one contains various
* control bits including the intercept vector and the second one contains
* the guest state.
*/
/* VMCB control area - padded up to 1024 bytes */
struct vmcb_ctrl {
uint32_t intercept[5]; /* all intercepts */
uint8_t pad1[0x28]; /* Offsets 0x14-0x3B are reserved. */
uint16_t pause_filthresh; /* Offset 0x3C, PAUSE filter threshold */
uint16_t pause_filcnt; /* Offset 0x3E, PAUSE filter count */
uint64_t iopm_base_pa; /* 0x40: IOPM_BASE_PA */
uint64_t msrpm_base_pa; /* 0x48: MSRPM_BASE_PA */
uint64_t tsc_offset; /* 0x50: TSC_OFFSET */
uint32_t asid; /* 0x58: Guest ASID */
uint8_t tlb_ctrl; /* 0x5C: TLB_CONTROL */
uint8_t pad2[3]; /* 0x5D-0x5F: Reserved. */
uint8_t v_tpr; /* 0x60: V_TPR, guest CR8 */
uint8_t v_irq:1; /* Is virtual interrupt pending? */
uint8_t :7; /* Padding */
uint8_t v_intr_prio:4; /* 0x62: Priority for virtual interrupt. */
uint8_t v_ign_tpr:1;
uint8_t :3;
uint8_t v_intr_masking:1; /* Guest and host sharing of RFLAGS. */
uint8_t :7;
uint8_t v_intr_vector; /* 0x64: Vector for virtual interrupt. */
uint8_t pad3[3]; /* 0x65-0x67 Reserved. */
uint64_t intr_shadow:1; /* 0x68: Interrupt shadow, section15.2.1 APM2 */
uint64_t :63;
uint64_t exitcode; /* 0x70, Exitcode */
uint64_t exitinfo1; /* 0x78, EXITINFO1 */
uint64_t exitinfo2; /* 0x80, EXITINFO2 */
uint64_t exitintinfo; /* 0x88, Interrupt exit value. */
uint64_t np_enable:1; /* 0x90, Nested paging enable. */
uint64_t :63;
uint8_t pad4[0x10]; /* 0x98-0xA7 reserved. */
uint64_t eventinj; /* 0xA8, Event injection. */
uint64_t n_cr3; /* B0, Nested page table. */
uint64_t lbr_virt_en:1; /* Enable LBR virtualization. */
uint64_t :63;
uint32_t vmcb_clean; /* 0xC0: VMCB clean bits for caching */
uint32_t :32; /* 0xC4: Reserved */
uint64_t nrip; /* 0xC8: Guest next nRIP. */
uint8_t inst_len; /* 0xD0: #NPF decode assist */
uint8_t inst_bytes[15];
uint8_t padd6[0x320];
} __attribute__ ((__packed__));
CTASSERT(sizeof(struct vmcb_ctrl) == 1024);
struct vmcb_state {
struct vmcb_segment es;
struct vmcb_segment cs;
struct vmcb_segment ss;
struct vmcb_segment ds;
struct vmcb_segment fs;
struct vmcb_segment gs;
struct vmcb_segment gdt;
struct vmcb_segment ldt;
struct vmcb_segment idt;
struct vmcb_segment tr;
uint8_t pad1[0x2b]; /* Reserved: 0xA0-0xCA */
uint8_t cpl;
uint8_t pad2[4];
uint64_t efer;
uint8_t pad3[0x70]; /* Reserved: 0xd8-0x147 */
uint64_t cr4;
uint64_t cr3; /* Guest CR3 */
uint64_t cr0;
uint64_t dr7;
uint64_t dr6;
uint64_t rflags;
uint64_t rip;
uint8_t pad4[0x58]; /* Reserved: 0x180-0x1D7 */
uint64_t rsp;
uint8_t pad5[0x18]; /* Reserved 0x1E0-0x1F7 */
uint64_t rax;
uint64_t star;
uint64_t lstar;
uint64_t cstar;
uint64_t sfmask;
uint64_t kernelgsbase;
uint64_t sysenter_cs;
uint64_t sysenter_esp;
uint64_t sysenter_eip;
uint64_t cr2;
uint8_t pad6[0x20];
uint64_t g_pat;
uint64_t dbgctl;
uint64_t br_from;
uint64_t br_to;
uint64_t int_from;
uint64_t int_to;
uint8_t pad7[0x968]; /* Reserved up to end of VMCB */
} __attribute__ ((__packed__));
CTASSERT(sizeof(struct vmcb_state) == 0xC00);
struct vmcb {
struct vmcb_ctrl ctrl;
struct vmcb_state state;
} __attribute__ ((__packed__));
CTASSERT(sizeof(struct vmcb) == PAGE_SIZE);
CTASSERT(offsetof(struct vmcb, state) == 0x400);
int vmcb_read(struct svm_softc *sc, int vcpu, int ident, uint64_t *retval);
int vmcb_write(struct svm_softc *sc, int vcpu, int ident, uint64_t val);
int vmcb_setdesc(void *arg, int vcpu, int ident, struct seg_desc *desc);
int vmcb_getdesc(void *arg, int vcpu, int ident, struct seg_desc *desc);
int vmcb_seg(struct vmcb *vmcb, int ident, struct vmcb_segment *seg);
#ifdef BHYVE_SNAPSHOT
int vmcb_getany(struct svm_softc *sc, int vcpu, int ident, uint64_t *val);
int vmcb_setany(struct svm_softc *sc, int vcpu, int ident, uint64_t val);
int vmcb_snapshot_desc(void *arg, int vcpu, int reg,
struct vm_snapshot_meta *meta);
int vmcb_snapshot_any(struct svm_softc *sc, int vcpu, int ident,
struct vm_snapshot_meta *meta);
#endif
#endif /* _KERNEL */
#endif /* _VMCB_H_ */
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