From: Zhao Liu <zhao1.liu@xxxxxxxxx>
The commit 154fb14df7a3c ("x86/hyperv: Replace kmap() with
kmap_local_page()") keeps the BUG_ON() to check if kmap_local_page()
fails.
But in fact, kmap_local_page() always returns a valid kernel address
and won't return NULL here. It will BUG on its own if it fails. [1]
So directly use memcpy_to_page() which creates local mapping to copy.
[1]: https://lore.kernel.org/lkml/YztFEyUA48et0yTt@iweiny-mobl/
Fixes: 154fb14df7a3 ("x86/hyperv: Replace kmap() with kmap_local_page()")
Suggested-by: Fabio M. De Francesco <fmdefrancesco@xxxxxxxxx>
Suggested-by: Ira Weiny <ira.weiny@xxxxxxxxx>
Signed-off-by: Zhao Liu <zhao1.liu@xxxxxxxxx>
---
arch/x86/hyperv/hv_init.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index 29774126e931..f66c5709324f 100644
--- a/arch/x86/hyperv/hv_init.c
+++ b/arch/x86/hyperv/hv_init.c
@@ -459,13 +459,11 @@ void __init hyperv_init(void)
wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
pg = vmalloc_to_page(hv_hypercall_pg);
- dst = kmap_local_page(pg);
src = memremap(hypercall_msr.guest_physical_address << PAGE_SHIFT, PAGE_SIZE,
MEMREMAP_WB);
- BUG_ON(!(src && dst));
- memcpy(dst, src, HV_HYP_PAGE_SIZE);
+ BUG_ON(!src);
+ memcpy_to_page(pg, 0, src, HV_HYP_PAGE_SIZE);
memunmap(src);
- kunmap_local(dst);
} else {
hypercall_msr.guest_physical_address = vmalloc_to_pfn(hv_hypercall_pg);
wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
--
2.34.1
