Porting Palacios to the Linux Kernel EECS441 – Resource Virtualization Steven Chen, Jason Lee,...

Porting Palacios to the Linux KernelEECS441 – Resource Virtualization

Steven Chen, Jason Lee, Pill Park

Overview Goals and Thoughts Visualization Approach Status Implementation

Functions Difficulties

Looking to the Future Acknowledgements, Thanks Questions

Chen, Lee, Park - Team Linux, EECS441

Goals and Thoughts Have the Palacios VMM embedded into Linux

Have Palacios compiled into Linux Have a guest successfully run in Palacios on Linux

Linux kernel host for Palacios Would facilitate more widespread usage of

Palacios Additional platform for Palacios

Current host OSes with Palacios embedded Kitten LWK (Sandia National Labs) GeekOS (University of Maryland)


Visualization

Palacios on Kitten Palacios on Linux


IA-32, x86-64x86-64, Cray XT

Kitten LWK Linux Kernel

Palacios VMM

Guest OS

Applications

Palacios VMM

Guest OS

Applications

LinuxApplications

Approach Initial Approach

Pattern matching between Kitten LWK, Linux kernel Tedious process May eventually be necessary anyways

Revised Approach Statically link Palacios to Linux build process Troubleshoot boot process

Troubleshoot Palacios load process Load guest blob Deal with panics Deal with unimplemented functions (pattern matching?)

Get to a terminal and working guest eventuallyChen, Lee, Park - Team Linux, EECS441

Status Statically link Palacios to Linux build process

Done Troubleshoot boot process

Troubleshoot Palacios load process Load guest blob

Done Deal with panics

In Progress Deal with unimplemented functions (pattern matching?)

In Progress

Get to a terminal and working guest eventually In Progress


Status – Serial Output


Implementation Statically Linking

Added lines to Makefile Links libv3vee.a into the Linux kernel666: # Link the LWK with the Palacios virtual machine monitor

667: libs-$(CONFIG_PALACIOS) += --whole-archive $(shell echo $(CONFIG_PALACIOS_PATH)/libv3vee.a) --no-whole-archive

Starting Palacios Added lines to init/main.c

847: int palacios_init(void);

896: #ifdef CONFIG_PALACIOS

897: palacios_init();

898: #endif


Functions – Adding print functionalityarch/x86/kernel/palacios/palacios.c

20 static void

21 palacios_print(

22 const char * fmt,

23 ...

24 )

25 {

26 va_list ap;

27 va_start(ap, fmt);

28 vprintk(fmt, ap);

29 va_end(ap);

30

31 return;

32 }


Functions – Panic for diagnosticsarch/x86/kernel/palacios/palacios.c

210 static void

211 palacios_interrupt_cpu(

212 struct guest_info * vm,

213 int cpu_id

214 )

215 {

216 panic("palacios_interrupt_cpu");

217 return;

218 }


Functions – Migrating Palacios’ Codearch/x86/kernel/palacios/palacios.c

alloc/free for Kitten alloc/free for Linux

static void *

palacios_alloc(unsigned int size)

{

return kmem_alloc(size);

}

static void

palacios_free(void * addr)

{

return kmem_free(addr);

}

static void *

palacios_alloc(unsigned int size)

{

return kmalloc(size, GFP_KERNEL);

}

static void

palacios_free(void * addr)

{

kfree(addr);

return;

}


Functions – Allocating Pagesarch/x86/kernel/palacios/palacios.c

static void *palacios_allocate_pages(int num_pages){ int order = 0; bool extra = false; printk("will get %d pages\n", num_pages); int i = 0; for(; i < 20; i++){ int temp = num_pages; if(num_pages > 1)

{ num_pages = num_pages / 2; order++; }

if(num_pages == 1)

{ if(extra) {order++;} break; } if((temp % 2) == 1) { extra = true; } }

if(order >= 14){ printk("Asked for order==%d, getting order==%d pages\n",order,14); order = 14; }

void *p = __get_free_pages(GFP_KERNEL, order);

if(p){ head = insert(head, (long long) p, order); p = __pa(p); return p; }


Functions – Freeing Pagesarch/x86/kernel/palacios/palacios.h

Will use a binary search tree to recall pages to be freed

struct node {

struct node* left;

struct node* right;

long long address;

int valid;

int order;

};

extern struct node* lookup(struct node* node, long long start_addr);

extern struct node* NewNode(long long ptr, int order);

extern struct node* insert(struct node* node, long long ptr, int order);


Functions – Freeing Pagesarch/x86/kernel/palacios/palacios.c

static void

palacios_free_page(

void * page_paddr

)

{

struct node* node = lookup(head, page_paddr);

free_pages(page_paddr, node->order);

node->valid = 0;

}


Functions – Freeing Pagesarch/x86/kernel/palacios/palacios.c

struct node* lookup(struct node* node, long long start_addr) { if (!node) { return 0; } else { if (start_addr == node->address) { return node; } else { if (start_addr < node->address) { return lookup(node->left, start_addr); } else { return lookup(node->right, start_addr); } } }}//end of the function


Functions – Making it by Faking itarch/x86/kernel/palacios/palacios.c

Getting to larger issues by hacking around smaller issues…

static unsigned int

palacios_get_cpu_khz(void)

{

printk("palacios_get_cpu_khz() lying to Palacios and saying 1

GHz\n");

return 1000000;

}


DifficultiesOS Hooks to Interrupts/** Structure used by the Palacios hypervisor to interface with the host kernel. */struct v3_os_hooks palacios_os_hooks = { .print = palacios_print, .allocate_pages = palacios_allocate_pages, .free_page = palacios_free_page, .malloc = palacios_alloc, .free = palacios_free, .vaddr_to_paddr = palacios_vaddr_to_paddr, .paddr_to_vaddr = palacios_paddr_to_vaddr, .hook_interrupt = palacios_hook_interrupt, .ack_irq = palacios_ack_interrupt, .get_cpu_khz = palacios_get_cpu_khz, .start_kernel_thread = palacios_start_kernel_thread, .yield_cpu = palacios_yield_cpu, .mutex_alloc = palacios_mutex_alloc, .mutex_free = palacios_mutex_free, .mutex_lock = palacios_mutex_lock, .mutex_unlock = palacios_mutex_unlock, .get_cpu = palacios_get_cpu, .interrupt_cpu = palacios_interrupt_cpu, .call_on_cpu = palacios_xcall, .start_thread_on_cpu = palacios_start_thread_on_cpu,};


Difficulties – Keyboard IRQsarch/x86/kernel/palacios/palacios.c

// hook keyboard host events for deliver to palaciosint i = 1;for(; i < 200; i++){ error = request_irq( i, &palacios_keyboard_interrupt, 0, "keyboard", NULL ); if(!error){ break; }}//for if(error){ printk("request irq for keyboard failed\n"); panic("request keyboard irq failed"); }


Looking to the Future Currently, 64MB limit on page_alloc

214 [16K] * 4KB pages = 64MB Short term - make a small guest Long term – resolve memory limits

Properly Implement Interrupts Improve the Palacios-Linux interface

Look to the Palacios-Kitten interface for reference

Have our code utilize Palacios data structures Support multi-core execution


Acknowledgements, Thanks Professor Peter Dinda UA Andy Gocke Lei Xia

V3VEE development group


Questions?


Porting Palacios to the Linux Kernel EECS441 – Resource Virtualization Steven Chen, Jason Lee,...

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