"d1cd12108346: x86, pageattr: Prevent overflow in slow_virt_to_phys() for X86_PAE"
was unintentionally removed by the recent
"34437e67a672: x86/mm: Fix slow_virt_to_phys() to handle large PAT bit".
And, the variable 'phys_addr' was defined as "unsigned long" by mistake -- it should
be "phys_addr_t".
As a result, Hyper-V network driver in 32-PAE Linux guest can't work again.
Fixes: "commmit 34437e67a672: x86/mm: Fix slow_virt_to_phys() to handle large PAT bit"
Signed-off-by: Dexuan Cui <decui@xxxxxxxxxxxxx>
Cc: Toshi Kani <toshi.kani@xxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: K. Y. Srinivasan <kys@xxxxxxxxxxxxx>
Cc: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>
Cc: gregkh@xxxxxxxxxxxxxxxxxxx
Cc: linux-mm@xxxxxxxxx
Cc: olaf@xxxxxxxxx
Cc: apw@xxxxxxxxxxxxx
Cc: jasowang@xxxxxxxxxx
Cc: stable@xxxxxxxxxxxxxxx
---
arch/x86/mm/pageattr.c | 14 ++++++++++----
1 file changed, 10 insertions(+), 4 deletions(-)
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 2440814..9cf96d8 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -419,24 +419,30 @@ pmd_t *lookup_pmd_address(unsigned long address)
phys_addr_t slow_virt_to_phys(void *__virt_addr)
{
unsigned long virt_addr = (unsigned long)__virt_addr;
- unsigned long phys_addr, offset;
+ phys_addr_t phys_addr;
+ unsigned long offset;
enum pg_level level;
pte_t *pte;
pte = lookup_address(virt_addr, &level);
BUG_ON(!pte);
+ /*
+ * pXX_pfn() returns unsigned long, which must be cast to phys_addr_t
+ * before being left-shifted PAGE_SHIFT bits -- this trick is to
+ * make 32-PAE kernel work correctly.
+ */
switch (level) {
case PG_LEVEL_1G:
- phys_addr = pud_pfn(*(pud_t *)pte) << PAGE_SHIFT;
+ phys_addr = (phys_addr_t)pud_pfn(*(pud_t *)pte) << PAGE_SHIFT;
offset = virt_addr & ~PUD_PAGE_MASK;
break;
case PG_LEVEL_2M:
- phys_addr = pmd_pfn(*(pmd_t *)pte) << PAGE_SHIFT;
+ phys_addr = (phys_addr_t)pmd_pfn(*(pmd_t *)pte) << PAGE_SHIFT;
offset = virt_addr & ~PMD_PAGE_MASK;
break;
default:
- phys_addr = pte_pfn(*pte) << PAGE_SHIFT;
+ phys_addr = (phys_addr_t)pte_pfn(*pte) << PAGE_SHIFT;
offset = virt_addr & ~PAGE_MASK;
}
--
1.9.1
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