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Commit 82f0712c authored by Borislav Petkov's avatar Borislav Petkov Committed by Matt Fleming
Browse files

x86/mm/cpa: Map in an arbitrary pgd 



Add the ability to map pages in an arbitrary pgd. This wires in the
remaining stuff so that there's a new interface with which you can map a
region into an arbitrary PGD.

Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Signed-off-by: default avatarMatt Fleming <matt.fleming@intel.com>
parent 52a628fb

arch/x86/mm/pageattr.c

+46 −7
Original line number Diff line number Diff line
@@ -453,7 +453,7 @@ try_preserve_large_page(pte_t *kpte, unsigned long address, 
	 * Check for races, another CPU might have split this page

	 * up already:

	 */

	tmp = lookup_address(address, &level);

	tmp = _lookup_address_cpa(cpa, address, &level);

	if (tmp != kpte)

		goto out_unlock;
@@ -559,7 +559,8 @@ try_preserve_large_page(pte_t *kpte, unsigned long address, 
}



static int

__split_large_page(pte_t *kpte, unsigned long address, struct page *base)

__split_large_page(struct cpa_data *cpa, pte_t *kpte, unsigned long address,

		   struct page *base)

{

	pte_t *pbase = (pte_t *)page_address(base);

	unsigned long pfn, pfninc = 1;
@@ -572,7 +573,7 @@ __split_large_page(pte_t *kpte, unsigned long address, struct page *base) 
	 * Check for races, another CPU might have split this page

	 * up for us already:

	 */

	tmp = lookup_address(address, &level);

	tmp = _lookup_address_cpa(cpa, address, &level);

	if (tmp != kpte) {

		spin_unlock(&pgd_lock);

		return 1;
@@ -648,7 +649,8 @@ __split_large_page(pte_t *kpte, unsigned long address, struct page *base) 
	return 0;

}



static int split_large_page(pte_t *kpte, unsigned long address)

static int split_large_page(struct cpa_data *cpa, pte_t *kpte,

			    unsigned long address)

{

	struct page *base;
@@ -660,7 +662,7 @@ static int split_large_page(pte_t *kpte, unsigned long address) 
	if (!base)

		return -ENOMEM;



	if (__split_large_page(kpte, address, base))

	if (__split_large_page(cpa, kpte, address, base))

		__free_page(base);



	return 0;
@@ -1041,6 +1043,9 @@ static int populate_pgd(struct cpa_data *cpa, unsigned long addr) 
static int __cpa_process_fault(struct cpa_data *cpa, unsigned long vaddr,

			       int primary)

{

	if (cpa->pgd)

		return populate_pgd(cpa, vaddr);



	/*

	 * Ignore all non primary paths.

	 */
@@ -1085,7 +1090,7 @@ static int __change_page_attr(struct cpa_data *cpa, int primary) 
	else

		address = *cpa->vaddr;

repeat:

	kpte = lookup_address(address, &level);

	kpte = _lookup_address_cpa(cpa, address, &level);

	if (!kpte)

		return __cpa_process_fault(cpa, address, primary);
@@ -1149,7 +1154,7 @@ static int __change_page_attr(struct cpa_data *cpa, int primary) 
	/*

	 * We have to split the large page:

	 */

	err = split_large_page(kpte, address);

	err = split_large_page(cpa, kpte, address);

	if (!err) {

		/*

	 	 * Do a global flush tlb after splitting the large page
@@ -1298,6 +1303,8 @@ static int change_page_attr_set_clr(unsigned long *addr, int numpages, 
	int ret, cache, checkalias;

	unsigned long baddr = 0;



	memset(&cpa, 0, sizeof(cpa));



	/*

	 * Check, if we are requested to change a not supported

	 * feature:
@@ -1744,6 +1751,7 @@ static int __set_pages_p(struct page *page, int numpages) 
{

	unsigned long tempaddr = (unsigned long) page_address(page);

	struct cpa_data cpa = { .vaddr = &tempaddr,

				.pgd = NULL,

				.numpages = numpages,

				.mask_set = __pgprot(_PAGE_PRESENT | _PAGE_RW),

				.mask_clr = __pgprot(0),
@@ -1762,6 +1770,7 @@ static int __set_pages_np(struct page *page, int numpages) 
{

	unsigned long tempaddr = (unsigned long) page_address(page);

	struct cpa_data cpa = { .vaddr = &tempaddr,

				.pgd = NULL,

				.numpages = numpages,

				.mask_set = __pgprot(0),

				.mask_clr = __pgprot(_PAGE_PRESENT | _PAGE_RW),
@@ -1822,6 +1831,36 @@ bool kernel_page_present(struct page *page) 


#endif /* CONFIG_DEBUG_PAGEALLOC */



int kernel_map_pages_in_pgd(pgd_t *pgd, u64 pfn, unsigned long address,

			    unsigned numpages, unsigned long page_flags)

{

	int retval = -EINVAL;



	struct cpa_data cpa = {

		.vaddr = &address,

		.pfn = pfn,

		.pgd = pgd,

		.numpages = numpages,

		.mask_set = __pgprot(0),

		.mask_clr = __pgprot(0),

		.flags = 0,

	};



	if (!(__supported_pte_mask & _PAGE_NX))

		goto out;



	if (!(page_flags & _PAGE_NX))

		cpa.mask_clr = __pgprot(_PAGE_NX);



	cpa.mask_set = __pgprot(_PAGE_PRESENT | page_flags);



	retval = __change_page_attr_set_clr(&cpa, 0);

	__flush_tlb_all();



out:

	return retval;

}



/*

 * The testcases use internal knowledge of the implementation that shouldn't

 * be exposed to the rest of the kernel. Include these directly here.