Commit 4c1ea3dd authored by Rusty Russell's avatar Rusty Russell
Browse files

lguest: use set_pte/set_pmd uniformly for real page table entries 



If we're building a pte, we can use simple assigment; only use set_pte
etc. when we're actually going to use that destination as a PTE.  I
don't know that we'll ever run under Xen, but it's neater.

And use set_pte/set_pmd rather than assuming native_ versions, even
though that's probably true for most people.

(Includes compile fix by Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>)
Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
Cc: Matias Zabaljauregui <zabaljauregui@gmail.com>
Cc: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
parent cdae0ad5

drivers/lguest/page_tables.c

+17 −22
Original line number Diff line number Diff line
@@ -380,7 +380,7 @@ bool demand_page(struct lg_cpu *cpu, unsigned long vaddr, int errcode) 
		 * And we copy the flags to the shadow PMD entry.  The page

		 * number in the shadow PMD is the page we just allocated.

		 */

		native_set_pmd(spmd, __pmd(__pa(ptepage) | pmd_flags(gpmd)));

		set_pmd(spmd, __pmd(__pa(ptepage) | pmd_flags(gpmd)));

	}



	/*
@@ -447,7 +447,7 @@ bool demand_page(struct lg_cpu *cpu, unsigned long vaddr, int errcode) 
		 * we will come back here when a write does actually occur, so

		 * we can update the Guest's _PAGE_DIRTY flag.

		 */

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

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



	/*

	 * Finally, we write the Guest PTE entry back: we've set the
@@ -528,7 +528,7 @@ static void release_pmd(pmd_t *spmd) 
		/* Now we can free the page of PTEs */

		free_page((long)ptepage);

		/* And zero out the PMD entry so we never release it twice. */

		native_set_pmd(spmd, __pmd(0));

		set_pmd(spmd, __pmd(0));

	}

}
@@ -833,7 +833,7 @@ static void do_set_pte(struct lg_cpu *cpu, int idx, 
			 */

			if (pte_flags(gpte) & (_PAGE_DIRTY | _PAGE_ACCESSED)) {

				check_gpte(cpu, gpte);

				native_set_pte(spte,

				set_pte(spte,

					gpte_to_spte(cpu, gpte,

						pte_flags(gpte) & _PAGE_DIRTY));

			} else {
@@ -841,7 +841,7 @@ static void do_set_pte(struct lg_cpu *cpu, int idx, 
				 * Otherwise kill it and we can demand_page()

				 * it in later.

				 */

				native_set_pte(spte, __pte(0));

				set_pte(spte, __pte(0));

			}

#ifdef CONFIG_X86_PAE

		}
@@ -983,16 +983,15 @@ static unsigned long setup_pagetables(struct lguest *lg, 
	 */

	for (i = j = 0; i < mapped_pages && j < PTRS_PER_PMD;

	     i += PTRS_PER_PTE, j++) {

		/* FIXME: native_set_pmd is overkill here. */

		native_set_pmd(&pmd, __pmd(((unsigned long)(linear + i)

		- mem_base) | _PAGE_PRESENT | _PAGE_RW | _PAGE_USER));

		pmd = pfn_pmd(((unsigned long)&linear[i] - mem_base)/PAGE_SIZE,

			      __pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_USER));



		if (copy_to_user(&pmds[j], &pmd, sizeof(pmd)) != 0)

			return -EFAULT;

	}



	/* One PGD entry, pointing to that PMD page. */

	set_pgd(&pgd, __pgd(((u32)pmds - mem_base) | _PAGE_PRESENT));

	pgd = __pgd(((unsigned long)pmds - mem_base) | _PAGE_PRESENT);

	/* Copy it in as the first PGD entry (ie. addresses 0-1G). */

	if (copy_to_user(&pgdir[0], &pgd, sizeof(pgd)) != 0)

		return -EFAULT;
@@ -1141,15 +1140,13 @@ void map_switcher_in_guest(struct lg_cpu *cpu, struct lguest_pages *pages) 
{

	pte_t *switcher_pte_page = __get_cpu_var(switcher_pte_pages);

	pte_t regs_pte;

	unsigned long pfn;



#ifdef CONFIG_X86_PAE

	pmd_t switcher_pmd;

	pmd_t *pmd_table;



	/* FIXME: native_set_pmd is overkill here. */

	native_set_pmd(&switcher_pmd, pfn_pmd(__pa(switcher_pte_page) >>

		       PAGE_SHIFT, PAGE_KERNEL_EXEC));

	switcher_pmd = pfn_pmd(__pa(switcher_pte_page) >> PAGE_SHIFT,

			       PAGE_KERNEL_EXEC);



	/* Figure out where the pmd page is, by reading the PGD, and converting

	 * it to a virtual address. */
@@ -1157,7 +1154,7 @@ void map_switcher_in_guest(struct lg_cpu *cpu, struct lguest_pages *pages) 
			pgdirs[cpu->cpu_pgd].pgdir[SWITCHER_PGD_INDEX])

								<< PAGE_SHIFT);

	/* Now write it into the shadow page table. */

	native_set_pmd(&pmd_table[SWITCHER_PMD_INDEX], switcher_pmd);

	set_pmd(&pmd_table[SWITCHER_PMD_INDEX], switcher_pmd);

#else

	pgd_t switcher_pgd;
@@ -1179,10 +1176,8 @@ 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;

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

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

			regs_pte);

	regs_pte = pfn_pte(__pa(cpu->regs_page) >> PAGE_SHIFT, PAGE_KERNEL);

	set_pte(&switcher_pte_page[pte_index((unsigned long)pages)], regs_pte);

}

/*:*/
@@ -1209,7 +1204,7 @@ 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++) {

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

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

				__pgprot(_PAGE_PRESENT|_PAGE_ACCESSED)));

	}
@@ -1217,14 +1212,14 @@ static __init void populate_switcher_pte_page(unsigned int cpu, 
	i = pages + cpu*2;



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

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

	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.

	 */

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

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

			   __pgprot(_PAGE_PRESENT|_PAGE_ACCESSED)));

}

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