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Commit 90603d15 authored by Matias Zabaljauregui's avatar Matias Zabaljauregui Committed by Rusty Russell
Browse files

lguest: use native_set_* macros, which properly handle 64-bit entries when PAE is activated 



Some cleanups and replace direct assignment with native_set_* macros which properly handle 64-bit entries when PAE is activated

Signed-off-by: default avatarMatias Zabaljauregui <zabaljauregui@gmail.com>
Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
parent ed1dc778

arch/x86/lguest/boot.c

+4 −4
Original line number Diff line number Diff line
@@ -525,7 +525,7 @@ static void lguest_pte_update(struct mm_struct *mm, unsigned long addr, 
static void lguest_set_pte_at(struct mm_struct *mm, unsigned long addr,

			      pte_t *ptep, pte_t pteval)

{

	*ptep = pteval;

	native_set_pte(ptep, pteval);

	lguest_pte_update(mm, addr, ptep);

}
@@ -534,9 +534,9 @@ static void lguest_set_pte_at(struct mm_struct *mm, unsigned long addr, 
 * changed. */

static void lguest_set_pmd(pmd_t *pmdp, pmd_t pmdval)

{

	*pmdp = pmdval;

	native_set_pmd(pmdp, pmdval);

	lazy_hcall2(LHCALL_SET_PMD, __pa(pmdp) & PAGE_MASK,

		   (__pa(pmdp) & (PAGE_SIZE - 1)) / 4);

		   (__pa(pmdp) & (PAGE_SIZE - 1)) / sizeof(pmd_t));

}



/* There are a couple of legacy places where the kernel sets a PTE, but we
@@ -550,7 +550,7 @@ static void lguest_set_pmd(pmd_t *pmdp, pmd_t pmdval) 
 * which brings boot back to 0.25 seconds. */

static void lguest_set_pte(pte_t *ptep, pte_t pteval)

{

	*ptep = pteval;

	native_set_pte(ptep, pteval);

	if (cr3_changed)

		lazy_hcall1(LHCALL_FLUSH_TLB, 1);

}

drivers/lguest/page_tables.c

+18 −17
Original line number Diff line number Diff line
@@ -90,7 +90,7 @@ static pte_t *spte_addr(pgd_t spgd, unsigned long vaddr) 
	pte_t *page = __va(pgd_pfn(spgd) << PAGE_SHIFT);

	/* You should never call this if the PGD entry wasn't valid */

	BUG_ON(!(pgd_flags(spgd) & _PAGE_PRESENT));

	return &page[(vaddr >> PAGE_SHIFT) % PTRS_PER_PTE];

	return &page[pte_index(vaddr)];

}



/* These two functions just like the above two, except they access the Guest
@@ -105,7 +105,7 @@ static unsigned long gpte_addr(pgd_t gpgd, unsigned long vaddr) 
{

	unsigned long gpage = pgd_pfn(gpgd) << PAGE_SHIFT;

	BUG_ON(!(pgd_flags(gpgd) & _PAGE_PRESENT));

	return gpage + ((vaddr>>PAGE_SHIFT) % PTRS_PER_PTE) * sizeof(pte_t);

	return gpage + pte_index(vaddr) * sizeof(pte_t);

}

/*:*/
@@ -171,7 +171,7 @@ static void release_pte(pte_t pte) 
	/* Remember that get_user_pages_fast() took a reference to the page, in

	 * get_pfn()?  We have to put it back now. */

	if (pte_flags(pte) & _PAGE_PRESENT)

		put_page(pfn_to_page(pte_pfn(pte)));

		put_page(pte_page(pte));

}

/*:*/
@@ -273,7 +273,7 @@ bool demand_page(struct lg_cpu *cpu, unsigned long vaddr, int errcode) 
		 * table entry, even if the Guest says it's writable.  That way

		 * we will come back here when a write does actually occur, so

		 * we can update the Guest's _PAGE_DIRTY flag. */

		*spte = gpte_to_spte(cpu, pte_wrprotect(gpte), 0);

		native_set_pte(spte, gpte_to_spte(cpu, pte_wrprotect(gpte), 0));



	/* Finally, we write the Guest PTE entry back: we've set the

	 * _PAGE_ACCESSED and maybe the _PAGE_DIRTY flags. */
@@ -323,7 +323,7 @@ void pin_page(struct lg_cpu *cpu, unsigned long vaddr) 
}



/*H:450 If we chase down the release_pgd() code, it looks like this: */

static void release_pgd(struct lguest *lg, pgd_t *spgd)

static void release_pgd(pgd_t *spgd)

{

	/* If the entry's not present, there's nothing to release. */

	if (pgd_flags(*spgd) & _PAGE_PRESENT) {
@@ -350,7 +350,7 @@ static void flush_user_mappings(struct lguest *lg, int idx) 
	unsigned int i;

	/* Release every pgd entry up to the kernel's address. */

	for (i = 0; i < pgd_index(lg->kernel_address); i++)

		release_pgd(lg, lg->pgdirs[idx].pgdir + i);

		release_pgd(lg->pgdirs[idx].pgdir + i);

}



/*H:440 (v) Flushing (throwing away) page tables,
@@ -431,7 +431,7 @@ static unsigned int new_pgdir(struct lg_cpu *cpu, 


/*H:430 (iv) Switching page tables

 *

 * Now we've seen all the page table setting and manipulation, let's see what

 * Now we've seen all the page table setting and manipulation, let's see

 * 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 lg_cpu *cpu, unsigned long pgtable)
@@ -463,7 +463,7 @@ static void release_all_pagetables(struct lguest *lg) 
		if (lg->pgdirs[i].pgdir)

			/* Every PGD entry except the Switcher at the top */

			for (j = 0; j < SWITCHER_PGD_INDEX; j++)

				release_pgd(lg, lg->pgdirs[i].pgdir + j);

				release_pgd(lg->pgdirs[i].pgdir + j);

}



/* We also throw away everything when a Guest tells us it's changed a kernel
@@ -581,7 +581,7 @@ void guest_set_pmd(struct lguest *lg, unsigned long gpgdir, u32 idx) 
	pgdir = find_pgdir(lg, gpgdir);

	if (pgdir < ARRAY_SIZE(lg->pgdirs))

		/* ... throw it away. */

		release_pgd(lg, lg->pgdirs[pgdir].pgdir + idx);

		release_pgd(lg->pgdirs[pgdir].pgdir + idx);

}



/* Once we know how much memory we have we can construct simple identity
@@ -726,8 +726,9 @@ void map_switcher_in_guest(struct lg_cpu *cpu, struct lguest_pages *pages) 
	 * page is already mapped there, we don't have to copy them out

	 * again. */

	pfn = __pa(cpu->regs_page) >> PAGE_SHIFT;

	regs_pte = pfn_pte(pfn, __pgprot(__PAGE_KERNEL));

	switcher_pte_page[(unsigned long)pages/PAGE_SIZE%PTRS_PER_PTE] = regs_pte;

	native_set_pte(&regs_pte, pfn_pte(pfn, PAGE_KERNEL));

	native_set_pte(&switcher_pte_page[pte_index((unsigned long)pages)],

			regs_pte);

}

/*:*/
@@ -752,21 +753,21 @@ static __init void populate_switcher_pte_page(unsigned int cpu, 


	/* The first entries are easy: they map the Switcher code. */

	for (i = 0; i < pages; i++) {

		pte[i] = mk_pte(switcher_page[i],

				__pgprot(_PAGE_PRESENT|_PAGE_ACCESSED));

		native_set_pte(&pte[i], mk_pte(switcher_page[i],

				__pgprot(_PAGE_PRESENT|_PAGE_ACCESSED)));

	}



	/* The only other thing we map is this CPU's pair of pages. */

	i = pages + cpu*2;



	/* First page (Guest registers) is writable from the Guest */

	pte[i] = pfn_pte(page_to_pfn(switcher_page[i]),

			 __pgprot(_PAGE_PRESENT|_PAGE_ACCESSED|_PAGE_RW));

	native_set_pte(&pte[i], pfn_pte(page_to_pfn(switcher_page[i]),

			 __pgprot(_PAGE_PRESENT|_PAGE_ACCESSED|_PAGE_RW)));



	/* The second page contains the "struct lguest_ro_state", and is

	 * read-only. */

	pte[i+1] = pfn_pte(page_to_pfn(switcher_page[i+1]),

			   __pgprot(_PAGE_PRESENT|_PAGE_ACCESSED));

	native_set_pte(&pte[i+1], pfn_pte(page_to_pfn(switcher_page[i+1]),

			   __pgprot(_PAGE_PRESENT|_PAGE_ACCESSED)));

}



/* We've made it through the page table code.  Perhaps our tired brains are