Re: [PATCH] vmware_guestdump: new input format

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Hi Alexey,

thanks for the patch, I've commented a few inline.

-----Original Message-----
> vmware_guestdump is extension to vmware_vmss with ability to debug
> debug.guest and debug.vmem files.
> 
> debug.guest.gz and debug.vmem.gz can be obtained using following
> .vmx options from VM running in debug mode:
>     monitor.mini-suspend_on_panic = TRUE
>     monitor.suspend_on_triplefault = TRUE
> 
> guestdump (debug.guest) is simplified version of *.vmss which does
> not contain full VM state, but minimal guest state, such as memory
> layout and CPUs state, needed for debugger. is_vmware_guestdump()
> and vmware_guestdump_init() functions parse guestdump header and
> populate vmss data structure (from vmware_vmss.c). As result, all
> handlers (except mempry_dump) from vmware_vmss.c can be reused.
> 
> How to use: $ crash debug.guest vmlinux
> debug.vmem must be present in the same folder as debug.guest.
> 
> Signed-off-by: Alexey Makhalov <amakhalov@xxxxxxxxxx>
> ---
>  Makefile           |   7 +-
>  defs.h             |   8 ++
>  filesys.c          |  12 ++-
>  main.c             |  14 +++
>  memory.c           |   8 +-
>  vmware_guestdump.c | 308 +++++++++++++++++++++++++++++++++++++++++++++++++++++
>  vmware_vmss.c      |   8 +-
>  vmware_vmss.h      |   8 ++
>  8 files changed, 359 insertions(+), 14 deletions(-)
>  create mode 100644 vmware_guestdump.c
> 
> diff --git a/Makefile b/Makefile
> index 7455410..d185719 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -70,7 +70,7 @@ CFILES=main.c tools.c global_data.c memory.c filesys.c help.c task.c \
>  	unwind_x86_32_64.c unwind_arm.c \
>  	xen_hyper.c xen_hyper_command.c xen_hyper_global_data.c \
>  	xen_hyper_dump_tables.c kvmdump.c qemu.c qemu-load.c sadump.c ipcs.c \
> -	ramdump.c vmware_vmss.c \
> +	ramdump.c vmware_vmss.c vmware_guestdump.c \
>  	xen_dom0.c kaslr_helper.c
> 
>  SOURCE_FILES=${CFILES} ${GENERIC_HFILES} ${MCORE_HFILES} \
> @@ -89,7 +89,7 @@ OBJECT_FILES=main.o tools.o global_data.o memory.o filesys.o help.o task.o \
>  	unwind_x86_32_64.o unwind_arm.o \
>  	xen_hyper.o xen_hyper_command.o xen_hyper_global_data.o \
>  	xen_hyper_dump_tables.o kvmdump.o qemu.o qemu-load.o sadump.o ipcs.o \
> -	ramdump.o vmware_vmss.o \
> +	ramdump.o vmware_vmss.o vmware_guestdump.o \
>  	xen_dom0.o kaslr_helper.o
> 
>  MEMORY_DRIVER_FILES=memory_driver/Makefile memory_driver/crash.c memory_driver/README
> @@ -518,6 +518,9 @@ ramdump.o: ${GENERIC_HFILES} ${REDHAT_HFILES} ramdump.c
>  vmware_vmss.o: ${GENERIC_HFILES} ${VMWARE_HFILES} vmware_vmss.c
>  	${CC} -c ${CRASH_CFLAGS} vmware_vmss.c ${WARNING_OPTIONS} ${WARNING_ERROR}
> 
> +vmware_guestdump.o: ${GENERIC_HFILES} ${VMWARE_HFILES} vmware_guestdump.c
> +	${CC} -c ${CRASH_CFLAGS} vmware_guestdump.c ${WARNING_OPTIONS} ${WARNING_ERROR}
> +
>  kaslr_helper.o: ${GENERIC_HFILES} kaslr_helper.c
>  	${CC} -c ${CRASH_CFLAGS} kaslr_helper.c ${WARNING_OPTIONS} ${WARNING_ERROR}
> 
> diff --git a/defs.h b/defs.h
> index c899fe2..f61f864 100644
> --- a/defs.h
> +++ b/defs.h
> @@ -655,6 +655,7 @@ struct new_utsname {
>  #define IRQ_DESC_TREE_RADIX        (0x40ULL)
>  #define IRQ_DESC_TREE_XARRAY       (0x80ULL)
>  #define KMOD_PAX                  (0x100ULL)
> +#define VMWARE_VMSS_GUESTDUMP     (0x200ULL)

It seems that this flag list is for kt->flags2, not pc->flags2.

(yes it's confusing.. I'd like to add a comment here in another chance)

> 
>  #define XEN()       (kt->flags & ARCH_XEN)
>  #define OPENVZ()    (kt->flags & ARCH_OPENVZ)
> @@ -6679,6 +6680,13 @@ int vmware_vmss_phys_base(ulong *phys_base);
>  int vmware_vmss_set_phys_base(ulong);
> 
>  /*
> + * vmware_guestdump.c
> + */
> +int is_vmware_guestdump(char *filename);
> +int vmware_guestdump_init(char *filename, FILE *ofp);
> +int vmware_guestdump_memory_dump(FILE *);
> +
> +/*
>   * kaslr_helper.c
>   */
>  int calc_kaslr_offset(ulong *, ulong *);
> diff --git a/filesys.c b/filesys.c
> index 2ec2b31..3361b6c 100644
> --- a/filesys.c
> +++ b/filesys.c
> @@ -253,9 +253,15 @@ memory_source_init(void)
>  				error(FATAL, "%s: initialization failed\n",
>                                          pc->dumpfile);
>  		} else if (pc->flags & VMWARE_VMSS) {
> -			if (!vmware_vmss_init(pc->dumpfile, fp))
> -				error(FATAL, "%s: initialization failed\n",
> -                                        pc->dumpfile);
> +			if (pc->flags2 & VMWARE_VMSS_GUESTDUMP) {
> +				if (!vmware_guestdump_init(pc->dumpfile, fp))
> +					error(FATAL, "%s: initialization failed\n",
> +						pc->dumpfile);
> +			} else {
> +				if (!vmware_vmss_init(pc->dumpfile, fp))
> +					error(FATAL, "%s: initialization failed\n",
> +						pc->dumpfile);
> +			}
>  		}
>  	}
>  }
> diff --git a/main.c b/main.c
> index 7f562e6..388ac46 100644
> --- a/main.c
> +++ b/main.c
> @@ -671,6 +671,18 @@ main(int argc, char **argv)
>  				pc->readmem = read_vmware_vmss;
>  				pc->writemem = write_vmware_vmss;
> 
> +			} else if (is_vmware_guestdump(argv[optind])) {
> +                                if (pc->flags & MEMORY_SOURCES) {
> +                                        error(INFO,
> +                                            "too many dumpfile arguments\n");
> +                                        program_usage(SHORT_FORM);
> +                                }
> +				pc->flags |= VMWARE_VMSS;
> +				pc->flags2 |= VMWARE_VMSS_GUESTDUMP;
> +				pc->dumpfile = argv[optind];
> +				pc->readmem = read_vmware_vmss;
> +				pc->writemem = write_vmware_vmss;
> +
>  			} else {
>  				error(INFO,
>  				    "%s: not a supported file format\n",
> @@ -1486,6 +1498,8 @@ dump_program_context(void)
>  		fprintf(fp, "%sMEMSRC_LOCAL", others++ ? "|" : "");
>  	if (pc->flags2 & REDZONE)
>  		fprintf(fp, "%sREDZONE", others++ ? "|" : "");
> +	if (pc->flags2 & VMWARE_VMSS_GUESTDUMP)
> +		fprintf(fp, "%sVMWARE_VMSS_GUESTDUMP", others++ ? "|" : "");
>  	fprintf(fp, ")\n");
> 
>  	fprintf(fp, "         namelist: %s\n", pc->namelist);
> diff --git a/memory.c b/memory.c
> index c951827..0848097 100644
> --- a/memory.c
> +++ b/memory.c
> @@ -17115,8 +17115,12 @@ dumpfile_memory(int cmd)
>                          retval = kcore_memory_dump(fp);
>  		else if (pc->flags & SADUMP)
>  			retval = sadump_memory_dump(fp);
> -		else if (pc->flags & VMWARE_VMSS)
> -			retval = vmware_vmss_memory_dump(fp);
> +		else if (pc->flags & VMWARE_VMSS) {
> +			if (pc->flags2 & VMWARE_VMSS_GUESTDUMP)
> +				retval = vmware_guestdump_memory_dump(fp);
> +			else
> +				retval = vmware_vmss_memory_dump(fp);
> +		}
>  		break;
> 
>  	case DUMPFILE_ENVIRONMENT:
> diff --git a/vmware_guestdump.c b/vmware_guestdump.c
> new file mode 100644
> index 0000000..45acb7a
> --- /dev/null
> +++ b/vmware_guestdump.c
> @@ -0,0 +1,308 @@
> +/*
> + * vmware_guestdump.c
> + *
> + * Copyright (c) 2020 VMware, Inc.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * Author: Alexey Makhalov <amakhalov@xxxxxxxxxx>
> + */
> +
> +#include "defs.h"
> +#include "vmware_vmss.h"
> +
> +#define LOGPRX "vmw: "
> +
> +#define GUESTDUMP_VERSION 4
> +#define GUESTDUMP_MAGIC1 1
> +#define GUESTDUMP_MAGIC2 0
> +
> +struct guestdumpheader {
> +	uint32_t version;
> +	uint32_t num_vcpus;
> +	uint8_t magic1;
> +	uint8_t reserved1;
> +	uint32_t cpu_vendor;
> +	uint64_t magic2;
> +	uint64_t last_addr;
> +	uint64_t memsize_in_pages;
> +	uint32_t reserved2;
> +	uint32_t mem_holes;
> +	struct memhole {
> +		uint64_t ppn;
> +		uint64_t pages;
> +	} holes[2];
> +} __attribute__((packed));
> +
> +struct vcpu_state {
> +	uint32_t cr0;
> +	uint64_t cr2;
> +	uint64_t cr3;
> +	uint64_t cr4;
> +	uint64_t reserved1[10];
> +	uint64_t idt_base;
> +	uint16_t reserved2[21];
> +	struct x86_64_pt_regs {
> +		uint64_t r15;
> +		uint64_t r14;
> +		uint64_t r13;
> +		uint64_t r12;
> +		uint64_t rbp;
> +		uint64_t rbx;
> +		uint64_t r11;
> +		uint64_t r10;
> +		uint64_t r9;
> +		uint64_t r8;
> +		uint64_t rax;
> +		uint64_t rcx;
> +		uint64_t rdx;
> +		uint64_t rsi;
> +		uint64_t rdi;
> +		uint64_t orig_rax;
> +		uint64_t rip;
> +		uint64_t cs;
> +		uint64_t eflags;
> +		uint64_t rsp;
> +		uint64_t ss;
> +	} regs64;
> +	uint8_t reserved3[65];
> +} __attribute__((packed));
> +
> +
> +/*
> + * vmware_guestdump is an extension to vmware_vmss with ability to debug
> + * debug.guest and debug.vmem files.
> + *
> + * debug.guest.gz and debug.vmem.gz can be obtained using following
> + * .vmx options from VM running in debug mode:
> + * 	monitor.mini-suspend_on_panic = TRUE
> + * 	monitor.suspend_on_triplefault = TRUE
> + *
> + * guestdump (debug.guest) is simplified version of *.vmss which does
> + * not contain full VM state, but minimal guest state, such as memory
> + * layout and CPUs state, needed for debugger. is_vmware_guestdump()
> + * and vmware_guestdump_init() functions parse guestdump header and
> + * populate vmss data structure (from vmware_vmss.c). As result, all
> + * handlers (except mempry_dump) from vmware_vmss.c can be reused.
> + *
> + */
> +
> +int
> +is_vmware_guestdump(char *filename)
> +{
> +	struct guestdumpheader hdr;
> +	FILE *fp;
> +	uint64_t filesize, holes_sum = 0;
> +	int i;
> +
> +	if (strcmp(basename(filename), "debug.guest"))
> +		return FALSE;

Just out of curiosity, renaming is not accepted and is it ok?
If it's renamed, how can they notice need to rename back to "debug.guest".

> +
> +        if ((fp = fopen(filename, "r")) == NULL) {
> +		error(INFO, LOGPRX"Failed to open '%s': [Error %d] %s\n",
> +		      filename, errno, strerror(errno));
> +		return FALSE;
> +        }
> +
> +	if (fread(&hdr, sizeof(struct guestdumpheader), 1, fp) != 1) {
> +		error(INFO, LOGPRX"Failed to read '%s': [Error %d] %s\n",
> +		      filename, errno, strerror(errno));
> +		fclose(fp);
> +		return FALSE;
> +	}
> +
> +	if (fseek(fp, 0L, SEEK_END) == -1) {
> +		error(INFO, LOGPRX"Failed to fseek '%s': [Error %d] %s\n",
> +		      filename, errno, strerror(errno));
> +		fclose(fp);
> +		return FALSE;
> +	}
> +	filesize = ftell(fp);
> +	fclose(fp);
> +
> +	for (i = 0; i < hdr.mem_holes; i++) {
> +		/* hole start page */
> +		vmss.regions[i].startpagenum = hdr.holes[i].ppn;
> +		/* hole end page */
> +		vmss.regions[i].startppn = hdr.holes[i].ppn + hdr.holes[i].pages;
> +		holes_sum += hdr.holes[i].pages;
> +	}

(hmm.. ah ok, hdr.mem_holes is less than 3 as checked below.)

> +
> +	if (hdr.version != GUESTDUMP_VERSION ||
> +	    hdr.magic1 != GUESTDUMP_MAGIC1 ||
> +	    hdr.magic2 != GUESTDUMP_MAGIC2 ||
> +	    hdr.mem_holes > 2 ||
> +	    (hdr.last_addr + 1) != ((hdr.memsize_in_pages + holes_sum) << VMW_PAGE_SHIFT) ||
> +	    filesize != sizeof(struct guestdumpheader) +
> +	    hdr.num_vcpus * (sizeof (struct vcpu_state) + VMW_PAGE_SIZE)) {
> +		if (CRASHDEBUG(1))
> +			error(INFO, LOGPRX"Unrecognized debug.guest file.\n");
> +		return FALSE;
> +	}
> +
> +	vmss.memsize = hdr.memsize_in_pages << VMW_PAGE_SHIFT;
> +	vmss.regionscount = hdr.mem_holes + 1;
> +	vmss.memoffset = 0;
> +	vmss.num_vcpus = hdr.num_vcpus;
> +	return TRUE;
> +}
> +
> +int
> +vmware_guestdump_init(char *filename, FILE *ofp)
> +{
> +	FILE *fp = NULL;
> +	int i, result = TRUE;
> +	char *vmem_filename = NULL;
> +	struct vcpu_state vs;
> +	char *p;
> +
> +	if (!machine_type("X86") && !machine_type("X86_64")) {
> +		error(INFO,
> +		      LOGPRX"Invalid or unsupported host architecture for .vmss file: %s\n",
> +		      MACHINE_TYPE);
> +		result = FALSE;
> +		goto exit;
> +	}
> +
> +        if ((fp = fopen(filename, "r")) == NULL) {
> +		error(INFO, LOGPRX"Failed to open '%s': [Error %d] %s\n",
> +		      filename, errno, strerror(errno));
> +		result = FALSE;
> +		goto exit;
> +        }
> +
> +	if (fseek(fp, sizeof(struct guestdumpheader), SEEK_SET) == -1) {
> +		error(INFO, LOGPRX"Failed to fseek '%s': [Error %d] %s\n",
> +		      filename, errno, strerror(errno));
> +		result = FALSE;
> +		goto exit;
> +	}
> +
> +	vmss.vcpu_regs = malloc(vmss.num_vcpus * sizeof(uint32_t));
> +	vmss.regs64 = calloc(vmss.num_vcpus, sizeof(void *));
> +	if (!vmss.vcpu_regs || !vmss.regs64) {
> +		error(INFO, LOGPRX"Failed to allocate memory\n");
> +		result = FALSE;
> +		goto exit;
> +	}
> +
> +	for (i = 0; i < vmss.num_vcpus; i++) {
> +		if (fread(&vs, sizeof(struct vcpu_state), 1, fp) != 1) {
> +			error(INFO, LOGPRX"Failed to read '%s': [Error %d] %s\n",
> +					filename, errno, strerror(errno));
> +			result = FALSE;
> +			goto exit;
> +		}
> +		vmss.regs64[i] = calloc(1, sizeof(vmssregs64));
> +		if (!vmss.regs64[i]) {
> +			error(INFO, LOGPRX"Failed to allocate memory\n");
> +			result = FALSE;
> +			goto exit;
> +		}
> +		vmss.vcpu_regs[i] = 0;
> +
> +		vmss.regs64[i]->rax = vs.regs64.rax;
> +		vmss.regs64[i]->rcx = vs.regs64.rcx;
> +		vmss.regs64[i]->rdx = vs.regs64.rdx;
> +		vmss.regs64[i]->rbx = vs.regs64.rbx;
> +		vmss.regs64[i]->rbp = vs.regs64.rbp;
> +		vmss.regs64[i]->rsp = vs.regs64.rsp;
> +		vmss.regs64[i]->rsi = vs.regs64.rsi;
> +		vmss.regs64[i]->rdi = vs.regs64.rdi;
> +		vmss.regs64[i]->r8 = vs.regs64.r8;
> +		vmss.regs64[i]->r9 = vs.regs64.r9;
> +		vmss.regs64[i]->r10 = vs.regs64.r10;
> +		vmss.regs64[i]->r11 = vs.regs64.r11;
> +		vmss.regs64[i]->r12 = vs.regs64.r12;
> +		vmss.regs64[i]->r13 = vs.regs64.r13;
> +		vmss.regs64[i]->r14 = vs.regs64.r14;
> +		vmss.regs64[i]->r15 = vs.regs64.r15;
> +		vmss.regs64[i]->idtr = vs.idt_base;
> +		vmss.regs64[i]->cr[0] = vs.cr0;
> +		vmss.regs64[i]->cr[2] = vs.cr2;
> +		vmss.regs64[i]->cr[3] = vs.cr3;
> +		vmss.regs64[i]->cr[4] = vs.cr4;
> +		vmss.regs64[i]->rip = vs.regs64.rip;
> +		vmss.regs64[i]->rflags = vs.regs64.eflags;
> +
> +		vmss.vcpu_regs[i] = REGS_PRESENT_ALL;
> +	}
> +
> +
> +	fprintf(ofp, LOGPRX"Try to locate the companion vmem file ...\n");
> +	vmem_filename = strdup(filename);
> +	p = vmem_filename + strlen(vmem_filename) - 5;
> +	if (strcmp(p, "guest") != 0) {
> +		result = FALSE;
> +		goto exit;
> +	}
> +	strcpy(p, "vmem");
> +	if ((vmss.dfp = fopen(vmem_filename, "r")) == NULL) {
> +		error(INFO, LOGPRX"%s: %s\n", vmem_filename, strerror(errno));
> +		result = FALSE;
> +		goto exit;
> +	}
> +	fseek(vmss.dfp, 0L, SEEK_END);
> +	if (vmss.memsize != ftell(vmss.dfp)) {
> +		error(INFO, LOGPRX"%s: unexpected size\n", vmem_filename);
> +		result = FALSE;
> +		goto exit;
> +	}
> +	fseek(vmss.dfp, 0L, SEEK_SET);
> +	fprintf(ofp, LOGPRX"vmem file: %s\n\n", vmem_filename);
> +
> +exit:
> +	if (fp)
> +		fclose(fp);
> +	if (vmem_filename)
> +		free(vmem_filename);
> +	if (result == FALSE) {
> +		if (vmss.dfp)
> +			fclose(vmss.dfp);
> +		if (vmss.regs64) {
> +			for (i = 0; i < vmss.num_vcpus; i++) {
> +				if (vmss.regs64[i])
> +					free(vmss.regs64[i]);
> +			}
> +			free(vmss.regs64);
> +		}
> +		if (vmss.vcpu_regs)
> +			free(vmss.vcpu_regs);
> +	}
> +	return result;
> +}
> +
> +int
> +vmware_guestdump_memory_dump(FILE *ofp)
> +{
> +	int result = TRUE;

The following warning is observed.

$ make clean
$ make warn
...
cc -c -g -DX86_64 -DSNAPPY -DLZO -DGDB_7_6  vmware_guestdump.c -Wall -O2 -Wstrict-prototypes -Wmissing-prototypes -fstack-protector -Wformat-security 
vmware_guestdump.c: In function ‘vmware_guestdump_memory_dump’:
vmware_guestdump.c:286:6: warning: unused variable ‘result’ [-Wunused-variable]
  int result = TRUE;
      ^

Thanks,
Kazu

> +	uint64_t holes_sum = 0;
> +	unsigned i;
> +
> +	fprintf(ofp, "vmware_guestdump:\n");
> +	fprintf(ofp, "    Header: version=%d num_vcpus=%ld\n",
> +		GUESTDUMP_VERSION, vmss.num_vcpus);
> +	fprintf(ofp, "Total memory: %ld\n", vmss.memsize);
> +
> +	if (vmss.regionscount > 1) {
> +		fprintf(ofp, "Memory regions[%d]:\n", vmss.regionscount);
> +		fprintf(ofp, "    [0x%016x-", 0);
> +		for (i = 0; i < vmss.regionscount - 1; i++) {
> +			fprintf(ofp, "0x%016lx]\n", (uint64_t)vmss.regions[i].startpagenum <<
> VMW_PAGE_SHIFT);
> +			fprintf(ofp, "    [0x%016lx-", (uint64_t)vmss.regions[i].startppn <<
> VMW_PAGE_SHIFT);
> +			holes_sum += vmss.regions[i].startppn - vmss.regions[i].startpagenum;
> +		}
> +		fprintf(ofp, "0x%016lx]\n", vmss.memsize + (holes_sum << VMW_PAGE_SHIFT));
> +	}
> +
> +	return TRUE;
> +}
> +
> diff --git a/vmware_vmss.c b/vmware_vmss.c
> index 252bfa2..b168f29 100644
> --- a/vmware_vmss.c
> +++ b/vmware_vmss.c
> @@ -23,13 +23,7 @@
> 
>  #define LOGPRX "vmw: "
> 
> -/* VMware only supports X86/X86_64 virtual machines. */
> -#define VMW_PAGE_SIZE (4096)
> -#define VMW_PAGE_SHIFT (12)
> -
> -#define MAX_BLOCK_DUMP (128)
> -
> -static vmssdata vmss = { 0 };
> +vmssdata vmss = { 0 };
> 
>  int
>  is_vmware_vmss(char *filename)
> diff --git a/vmware_vmss.h b/vmware_vmss.h
> index a5828a0..01d9446 100644
> --- a/vmware_vmss.h
> +++ b/vmware_vmss.h
> @@ -165,6 +165,14 @@ struct vmssdata {
>  };
>  typedef struct vmssdata vmssdata;
> 
> +/* VMware only supports X86/X86_64 virtual machines. */
> +#define VMW_PAGE_SIZE (4096)
> +#define VMW_PAGE_SHIFT (12)
> +
> +#define MAX_BLOCK_DUMP (128)
> +
> +extern vmssdata vmss;
> +
>  #define DEBUG_PARSE_PRINT(x)		\
>  do {					\
>  	if (CRASHDEBUG(1)) {		\
> --
> 2.11.0
> 
> --
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> Crash-utility@xxxxxxxxxx
> https://www.redhat.com/mailman/listinfo/crash-utility


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