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Commit 4665ac8e authored by Glauber de Oliveira Costa's avatar Glauber de Oliveira Costa Committed by Rusty Russell
Browse files

lguest: makes special fields be per-vcpu 



lguest struct have room for some fields, namely, cr2, ts, esp1
and ss1, that are not really guest-wide, but rather, vcpu-wide.

This patch puts it in the vcpu struct

Signed-off-by: default avatarGlauber de Oliveira Costa <gcosta@redhat.com>
Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
parent 66686c2a

drivers/lguest/hypercalls.c

+5 −5
Original line number Diff line number Diff line
@@ -60,7 +60,7 @@ static void do_hcall(struct lg_cpu *cpu, struct hcall_args *args) 
		/* FLUSH_TLB comes in two flavors, depending on the

		 * argument: */

		if (args->arg1)

			guest_pagetable_clear_all(lg);

			guest_pagetable_clear_all(cpu);

		else

			guest_pagetable_flush_user(lg);

		break;
@@ -68,10 +68,10 @@ static void do_hcall(struct lg_cpu *cpu, struct hcall_args *args) 
	/* All these calls simply pass the arguments through to the right

	 * routines. */

	case LHCALL_NEW_PGTABLE:

		guest_new_pagetable(lg, args->arg1);

		guest_new_pagetable(cpu, args->arg1);

		break;

	case LHCALL_SET_STACK:

		guest_set_stack(lg, args->arg1, args->arg2, args->arg3);

		guest_set_stack(cpu, args->arg1, args->arg2, args->arg3);

		break;

	case LHCALL_SET_PTE:

		guest_set_pte(lg, args->arg1, args->arg2, __pte(args->arg3));
@@ -84,7 +84,7 @@ static void do_hcall(struct lg_cpu *cpu, struct hcall_args *args) 
		break;

	case LHCALL_TS:

		/* This sets the TS flag, as we saw used in run_guest(). */

		lg->ts = args->arg1;

		cpu->ts = args->arg1;

		break;

	case LHCALL_HALT:

		/* Similarly, this sets the halted flag for run_guest(). */
@@ -191,7 +191,7 @@ static void initialize(struct lg_cpu *cpu) 
	 * first write to a Guest page.  This may have caused a copy-on-write

	 * fault, but the old page might be (read-only) in the Guest

	 * pagetable. */

	guest_pagetable_clear_all(lg);

	guest_pagetable_clear_all(cpu);

}



/*H:100

drivers/lguest/interrupts_and_traps.c

+12 −11
Original line number Diff line number Diff line
@@ -73,8 +73,8 @@ static void set_guest_interrupt(struct lg_cpu *cpu, u32 lo, u32 hi, int has_err) 
	if ((cpu->regs->ss&0x3) != GUEST_PL) {

		/* The Guest told us their kernel stack with the SET_STACK

		 * hypercall: both the virtual address and the segment */

		virtstack = lg->esp1;

		ss = lg->ss1;

		virtstack = cpu->esp1;

		ss = cpu->ss1;



		origstack = gstack = guest_pa(lg, virtstack);

		/* We push the old stack segment and pointer onto the new
@@ -311,10 +311,11 @@ static int direct_trap(unsigned int num) 
 * the Guest.

 *

 * Which is deeply unfair, because (literally!) it wasn't the Guests' fault. */

void pin_stack_pages(struct lguest *lg)

void pin_stack_pages(struct lg_cpu *cpu)

{

	unsigned int i;



	struct lguest *lg = cpu->lg;

	/* Depending on the CONFIG_4KSTACKS option, the Guest can have one or

	 * two pages of stack space. */

	for (i = 0; i < lg->stack_pages; i++)
@@ -322,7 +323,7 @@ void pin_stack_pages(struct lguest *lg) 
		 * start of the page after the kernel stack.  Subtract one to

		 * get back onto the first stack page, and keep subtracting to

		 * get to the rest of the stack pages. */

		pin_page(lg, lg->esp1 - 1 - i * PAGE_SIZE);

		pin_page(lg, cpu->esp1 - 1 - i * PAGE_SIZE);

}



/* Direct traps also mean that we need to know whenever the Guest wants to use
@@ -333,21 +334,21 @@ void pin_stack_pages(struct lguest *lg) 
 *

 * In Linux each process has its own kernel stack, so this happens a lot: we

 * change stacks on each context switch. */

void guest_set_stack(struct lguest *lg, u32 seg, u32 esp, unsigned int pages)

void guest_set_stack(struct lg_cpu *cpu, u32 seg, u32 esp, unsigned int pages)

{

	/* You are not allowed have a stack segment with privilege level 0: bad

	 * Guest! */

	if ((seg & 0x3) != GUEST_PL)

		kill_guest(lg, "bad stack segment %i", seg);

		kill_guest(cpu->lg, "bad stack segment %i", seg);

	/* We only expect one or two stack pages. */

	if (pages > 2)

		kill_guest(lg, "bad stack pages %u", pages);

		kill_guest(cpu->lg, "bad stack pages %u", pages);

	/* Save where the stack is, and how many pages */

	lg->ss1 = seg;

	lg->esp1 = esp;

	lg->stack_pages = pages;

	cpu->ss1 = seg;

	cpu->esp1 = esp;

	cpu->lg->stack_pages = pages;

	/* Make sure the new stack pages are mapped */

	pin_stack_pages(lg);

	pin_stack_pages(cpu);

}



/* All this reference to mapping stacks leads us neatly into the other complex

drivers/lguest/lg.h

+9 −8
Original line number Diff line number Diff line
@@ -46,6 +46,11 @@ struct lg_cpu { 
	struct task_struct *tsk;

	struct mm_struct *mm; 	/* == tsk->mm, but that becomes NULL on exit */



	u32 cr2;

	int ts;

	u32 esp1;

	u8 ss1;



	/* At end of a page shared mapped over lguest_pages in guest.  */

	unsigned long regs_page;

	struct lguest_regs *regs;
@@ -80,10 +85,6 @@ struct lguest 
	 * memory in the Launcher. */

	void __user *mem_base;

	unsigned long kernel_address;

	u32 cr2;

	int ts;

	u32 esp1;

	u8 ss1;



	/* Bitmap of what has changed: see CHANGED_* above. */

	int changed;
@@ -141,8 +142,8 @@ void maybe_do_interrupt(struct lg_cpu *cpu); 
int deliver_trap(struct lg_cpu *cpu, unsigned int num);

void load_guest_idt_entry(struct lg_cpu *cpu, unsigned int i,

			  u32 low, u32 hi);

void guest_set_stack(struct lguest *lg, u32 seg, u32 esp, unsigned int pages);

void pin_stack_pages(struct lguest *lg);

void guest_set_stack(struct lg_cpu *cpu, u32 seg, u32 esp, unsigned int pages);

void pin_stack_pages(struct lg_cpu *cpu);

void setup_default_idt_entries(struct lguest_ro_state *state,

			       const unsigned long *def);

void copy_traps(const struct lg_cpu *cpu, struct desc_struct *idt,
@@ -164,9 +165,9 @@ void copy_gdt_tls(const struct lg_cpu *cpu, struct desc_struct *gdt); 
/* page_tables.c: */

int init_guest_pagetable(struct lguest *lg, unsigned long pgtable);

void free_guest_pagetable(struct lguest *lg);

void guest_new_pagetable(struct lguest *lg, unsigned long pgtable);

void guest_new_pagetable(struct lg_cpu *cpu, unsigned long pgtable);

void guest_set_pmd(struct lguest *lg, unsigned long gpgdir, u32 i);

void guest_pagetable_clear_all(struct lguest *lg);

void guest_pagetable_clear_all(struct lg_cpu *cpu);

void guest_pagetable_flush_user(struct lguest *lg);

void guest_set_pte(struct lguest *lg, unsigned long gpgdir,

		   unsigned long vaddr, pte_t val);

drivers/lguest/page_tables.c

+6 −5
Original line number Diff line number Diff line
@@ -432,9 +432,10 @@ static unsigned int new_pgdir(struct lguest *lg, 
 * Now we've seen all the page table setting and manipulation, let's see what

 * what happens when the Guest changes page tables (ie. changes the top-level

 * pgdir).  This occurs on almost every context switch. */

void guest_new_pagetable(struct lguest *lg, unsigned long pgtable)

void guest_new_pagetable(struct lg_cpu *cpu, unsigned long pgtable)

{

	int newpgdir, repin = 0;

	struct lguest *lg = cpu->lg;



	/* Look to see if we have this one already. */

	newpgdir = find_pgdir(lg, pgtable);
@@ -446,7 +447,7 @@ void guest_new_pagetable(struct lguest *lg, unsigned long pgtable) 
	lg->pgdidx = newpgdir;

	/* If it was completely blank, we map in the Guest kernel stack */

	if (repin)

		pin_stack_pages(lg);

		pin_stack_pages(cpu);

}



/*H:470 Finally, a routine which throws away everything: all PGD entries in all
@@ -468,11 +469,11 @@ static void release_all_pagetables(struct lguest *lg) 
 * mapping.  Since kernel mappings are in every page table, it's easiest to

 * throw them all away.  This traps the Guest in amber for a while as

 * everything faults back in, but it's rare. */

void guest_pagetable_clear_all(struct lguest *lg)

void guest_pagetable_clear_all(struct lg_cpu *cpu)

{

	release_all_pagetables(lg);

	release_all_pagetables(cpu->lg);

	/* We need the Guest kernel stack mapped again. */

	pin_stack_pages(lg);

	pin_stack_pages(cpu);

}

/*:*/

/*M:009 Since we throw away all mappings when a kernel mapping changes, our

drivers/lguest/x86/core.c

+4 −6
Original line number Diff line number Diff line
@@ -95,8 +95,8 @@ static void copy_in_guest_info(struct lg_cpu *cpu, struct lguest_pages *pages) 
	/* Set up the two "TSS" members which tell the CPU what stack to use

	 * for traps which do directly into the Guest (ie. traps at privilege

	 * level 1). */

	pages->state.guest_tss.esp1 = lg->esp1;

	pages->state.guest_tss.ss1 = lg->ss1;

	pages->state.guest_tss.esp1 = cpu->esp1;

	pages->state.guest_tss.ss1 = cpu->ss1;



	/* Copy direct-to-Guest trap entries. */

	if (lg->changed & CHANGED_IDT)
@@ -165,12 +165,10 @@ static void run_guest_once(struct lg_cpu *cpu, struct lguest_pages *pages) 
 * are disabled: we own the CPU. */

void lguest_arch_run_guest(struct lg_cpu *cpu)

{

	struct lguest *lg = cpu->lg;



	/* Remember the awfully-named TS bit?  If the Guest has asked to set it

	 * we set it now, so we can trap and pass that trap to the Guest if it

	 * uses the FPU. */

	if (lg->ts)

	if (cpu->ts)

		lguest_set_ts();



	/* SYSENTER is an optimized way of doing system calls.  We can't allow
@@ -325,7 +323,7 @@ void lguest_arch_handle_trap(struct lg_cpu *cpu) 
		/* If the Guest doesn't want to know, we already restored the

		 * Floating Point Unit, so we just continue without telling

		 * it. */

		if (!lg->ts)

		if (!cpu->ts)

			return;

		break;

	case 32 ... 255: