From: Long Li longli@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: stable@vger.kernel.org Fixes: ca48739e59df ("Drivers: hv: vmbus: Move Hyper-V page allocator to arch neutral code") Signed-off-by: Long Li longli@microsoft.com --- drivers/hv/hv_common.c | 35 ++++++++++------------------------- 1 file changed, 10 insertions(+), 25 deletions(-)
diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c index a7d7494feaca..297ccd7d4997 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);
@@ -272,7 +257,7 @@ static void hv_kmsg_dump_unregister(void) atomic_notifier_chain_unregister(&panic_notifier_list, &hyperv_panic_report_block);
- hv_free_hyperv_page(hv_panic_page); + kfree(hv_panic_page); hv_panic_page = NULL; }
@@ -280,7 +265,7 @@ static void hv_kmsg_dump_register(void) { int ret;
- hv_panic_page = hv_alloc_hyperv_zeroed_page(); + hv_panic_page = kzalloc(HV_HYP_PAGE_SIZE, GFP_KERNEL); if (!hv_panic_page) { pr_err("Hyper-V: panic message page memory allocation failed\n"); return; @@ -289,7 +274,7 @@ static void hv_kmsg_dump_register(void) ret = kmsg_dump_register(&hv_kmsg_dumper); if (ret) { pr_err("Hyper-V: kmsg dump register error 0x%x\n", ret); - hv_free_hyperv_page(hv_panic_page); + kfree(hv_panic_page); hv_panic_page = NULL; } }