From: Long Li <lon...@microsoft.com>
There are use cases that interrupt and monitor pages are mapped to
user-mode through UIO, they need to be system page aligned. Some Hyper-V
allocation APIs introduced earlier broke those requirements.
Fix those APIs by always allocating Hyper-V page at system page boundaries.
Cc: sta...@vger.kernel.org
Fixes: ca48739e59df ("Drivers: hv: vmbus: Move Hyper-V page allocator to arch
neutral code")
Signed-off-by: Long Li <lon...@microsoft.com>
---
drivers/hv/hv_common.c | 29 +++++++----------------------
1 file changed, 7 insertions(+), 22 deletions(-)
diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c
index a7d7494feaca..f426aaa9b8f9 100644
--- a/drivers/hv/hv_common.c
+++ b/drivers/hv/hv_common.c
@@ -106,41 +106,26 @@ void __init hv_common_free(void)
}
/*
- * Functions for allocating and freeing memory with size and
- * alignment HV_HYP_PAGE_SIZE. These functions are needed because
- * the guest page size may not be the same as the Hyper-V page
- * size. We depend upon kmalloc() aligning power-of-two size
- * allocations to the allocation size boundary, so that the
- * allocated memory appears to Hyper-V as a page of the size
- * it expects.
+ * A Hyper-V page can be used by UIO for mapping to user-space, it should
+ * always be allocated on system page boundaries.
*/
-
void *hv_alloc_hyperv_page(void)
{
- BUILD_BUG_ON(PAGE_SIZE < HV_HYP_PAGE_SIZE);
-
- if (PAGE_SIZE == HV_HYP_PAGE_SIZE)
- return (void *)__get_free_page(GFP_KERNEL);
- else
- return kmalloc(HV_HYP_PAGE_SIZE, GFP_KERNEL);
+ BUILD_BUG_ON(PAGE_SIZE < HV_HYP_PAGE_SIZE);
+ return (void *)__get_free_page(GFP_KERNEL);
}
EXPORT_SYMBOL_GPL(hv_alloc_hyperv_page);
void *hv_alloc_hyperv_zeroed_page(void)
{
- if (PAGE_SIZE == HV_HYP_PAGE_SIZE)
- return (void *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
- else
- return kzalloc(HV_HYP_PAGE_SIZE, GFP_KERNEL);
+ BUILD_BUG_ON(PAGE_SIZE < HV_HYP_PAGE_SIZE);
+ return (void *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
}
EXPORT_SYMBOL_GPL(hv_alloc_hyperv_zeroed_page);
void hv_free_hyperv_page(void *addr)
{
- if (PAGE_SIZE == HV_HYP_PAGE_SIZE)
- free_page((unsigned long)addr);
- else
- kfree(addr);
+ free_page((unsigned long)addr);
}
EXPORT_SYMBOL_GPL(hv_free_hyperv_page);
--
2.34.1
