Messages in this thread | | | Date | Tue, 20 Jul 2021 15:54:37 +0200 | From | Christoph Hellwig <> | Subject | Re: [Resend RFC PATCH V4 09/13] x86/Swiotlb/HV: Add Swiotlb bounce buffer remap function for HV IVM |
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Please split the swiotlb changes into a separate patch from the consumer.
> } > + > +/* > + * hv_map_memory - map memory to extra space in the AMD SEV-SNP Isolation VM. > + */ > +unsigned long hv_map_memory(unsigned long addr, unsigned long size) > +{ > + unsigned long *pfns = kcalloc(size / HV_HYP_PAGE_SIZE, > + sizeof(unsigned long), > + GFP_KERNEL); > + unsigned long vaddr; > + int i; > + > + if (!pfns) > + return (unsigned long)NULL; > + > + for (i = 0; i < size / HV_HYP_PAGE_SIZE; i++) > + pfns[i] = virt_to_hvpfn((void *)addr + i * HV_HYP_PAGE_SIZE) + > + (ms_hyperv.shared_gpa_boundary >> HV_HYP_PAGE_SHIFT); > + > + vaddr = (unsigned long)vmap_pfn(pfns, size / HV_HYP_PAGE_SIZE, > + PAGE_KERNEL_IO); > + kfree(pfns); > + > + return vaddr;
This seems to miss a 'select VMAP_PFN'. But more importantly I don't think this actually works. Various DMA APIs do expect a struct page backing, so how is this going to work with say dma_mmap_attrs or dma_get_sgtable_attrs?
> +static unsigned long __map_memory(unsigned long addr, unsigned long size) > +{ > + if (hv_is_isolation_supported()) > + return hv_map_memory(addr, size); > + > + return addr; > +} > + > +static void __unmap_memory(unsigned long addr) > +{ > + if (hv_is_isolation_supported()) > + hv_unmap_memory(addr); > +} > + > +unsigned long set_memory_decrypted_map(unsigned long addr, unsigned long size) > +{ > + if (__set_memory_enc_dec(addr, size / PAGE_SIZE, false)) > + return (unsigned long)NULL; > + > + return __map_memory(addr, size); > +} > + > +int set_memory_encrypted_unmap(unsigned long addr, unsigned long size) > +{ > + __unmap_memory(addr); > + return __set_memory_enc_dec(addr, size / PAGE_SIZE, true); > +}
Why this obsfucation into all kinds of strange helpers? Also I think we want an ops vectors (or alternative calls) instead of the random if checks here.
> + * @vstart: The virtual start address of the swiotlb memory pool. The swiotlb > + * memory pool may be remapped in the memory encrypted case and store
Normall we'd call this vaddr or cpu_addr.
> - set_memory_decrypted((unsigned long)vaddr, bytes >> PAGE_SHIFT); > - memset(vaddr, 0, bytes); > + mem->vstart = (void *)set_memory_decrypted_map((unsigned long)vaddr, bytes);
Please always pass kernel virtual addresses as pointers.
And I think these APIs might need better names, e.g.
arch_dma_map_decrypted and arch_dma_unmap_decrypted.
Also these will need fallback versions for non-x86 architectures that currently use memory encryption.
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