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: Borislav Petkov <bp@suse.de>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>

diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index db8ace29514f3a158bed721dad3cb4992e947c93..b3b19f46c0164c7169c9259a68836afbaeae1943 100644 (file)
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -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 @@ out_unlock:
 }
 
 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 @@ repeat:
        /*
         * 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.