On Fri, Sep 02, 2022, Zhao Liu wrote: > From: Zhao Liu <zhao1.liu@xxxxxxxxx> > > The use of kmap_atomic() is being deprecated in favor of > kmap_local_page()[1]. > > In arch/x86/kvm/svm/sev.c, the function sev_clflush_pages() doesn't > need to disable pagefaults and preemption in kmap_atomic(). It can > simply use kmap_local_page() / kunmap_local() that can instead do the > mapping / unmapping regardless of the context. > > With kmap_local_page(), the mapping is per thread, CPU local and not > globally visible. Therefore, sev_clflush_pages() is a function where > the use of kmap_local_page() in place of kmap_atomic() is correctly > suited. > > Convert the calls of kmap_atomic() / kunmap_atomic() to > kmap_local_page() / kunmap_local(). > > [1]: https://lore.kernel.org/all/20220813220034.806698-1-ira.weiny@xxxxxxxxx > > Suggested-by: Ira Weiny <ira.weiny@xxxxxxxxx> > Suggested-by: Fabio M. De Francesco <fmdefrancesco@xxxxxxxxx> > Signed-off-by: Zhao Liu <zhao1.liu@xxxxxxxxx> > --- > Suggested by credits. > Ira: Referred to his task document and review comments. > Fabio: Referred to his boiler plate commit message. > --- > arch/x86/kvm/svm/sev.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c > index 28064060413a..12747c7bda4e 100644 > --- a/arch/x86/kvm/svm/sev.c > +++ b/arch/x86/kvm/svm/sev.c > @@ -465,9 +465,9 @@ static void sev_clflush_pages(struct page *pages[], unsigned long npages) > return; > > for (i = 0; i < npages; i++) { > - page_virtual = kmap_atomic(pages[i]); > + page_virtual = kmap_local_page(pages[i]); > clflush_cache_range(page_virtual, PAGE_SIZE); SEV is 64-bit only, any reason not to go straight to page_address()? diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index 28064060413a..aaf39e3c7bb5 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -457,7 +457,6 @@ static void sev_unpin_memory(struct kvm *kvm, struct page **pages, static void sev_clflush_pages(struct page *pages[], unsigned long npages) { - uint8_t *page_virtual; unsigned long i; if (this_cpu_has(X86_FEATURE_SME_COHERENT) || npages == 0 || @@ -465,9 +464,7 @@ static void sev_clflush_pages(struct page *pages[], unsigned long npages) return; for (i = 0; i < npages; i++) { - page_virtual = kmap_atomic(pages[i]); - clflush_cache_range(page_virtual, PAGE_SIZE); - kunmap_atomic(page_virtual); + clflush_cache_range(page_address(pages[i]), PAGE_SIZE); cond_resched(); } } config KVM_AMD_SEV def_bool y bool "AMD Secure Encrypted Virtualization (SEV) support" depends on KVM_AMD && X86_64 <================================== > - kunmap_atomic(page_virtual); > + kunmap_local(page_virtual); > cond_resched(); > } > } > -- > 2.34.1 >
