Messages in this thread |  | | From | "Kalra, Ashish" <> | Subject | RE: [PATCH Part2 v6 05/49] x86/sev: Add RMP entry lookup helpers | Date | Mon, 1 Aug 2022 21:45:05 +0000 |
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[AMD Official Use Only - General]
Hello Boris,
>> +static struct rmpentry *__snp_lookup_rmpentry(u64 pfn, int *level) { >> + unsigned long vaddr, paddr = pfn << PAGE_SHIFT; >> + struct rmpentry *entry, *large_entry; >.> + >> + if (!pfn_valid(pfn)) >> + return ERR_PTR(-EINVAL); >> + >> + if (!cpu_feature_enabled(X86_FEATURE_SEV_SNP)) >> + return ERR_PTR(-ENXIO);
>That test should happen first. Ok.
>> + vaddr = rmptable_start + rmptable_page_offset(paddr);
>Wait, what does that macro do?
>It takes the physical address and gives the offset from the beginning of the RMP table in VA space?
>So why don't you do
> entry = rmptable_entry(paddr)
>instead which simply gives you directly the entry in the RMP table with which you can work further?
>Instead of this macro doing half the work and then callers having to add the RMP start address and cast.
>And make it small function so that you can have typechecking too, while at it.
Ok, I will add a new corresponding rmptable_entry() function here, should be usable for getting the large RMP entry below too.
>> + if (unlikely(vaddr > rmptable_end)) >> + return ERR_PTR(-ENXIO); >> + >> + entry = (struct rmpentry *)vaddr; >> + >> + /* Read a large RMP entry to get the correct page level used in RMP entry. */ >> + vaddr = rmptable_start + rmptable_page_offset(paddr & PMD_MASK); >> + large_entry = (struct rmpentry *)vaddr; >> + *level = RMP_TO_X86_PG_LEVEL(rmpentry_pagesize(large_entry)); >> + >> + return entry; >> +} >> + >> +/* >> diff --git a/include/linux/sev.h b/include/linux/sev.h new file mode >> 100644 index 000000000000..1a68842789e1 >> --- /dev/null >> +++ b/include/linux/sev.h
>Why is this header in the linux/ namespace and not in arch/x86/ ?
>All that stuff in here doesn't have any meaning outside of x86...
Yes, makes sense to move it to arch/x86.
Thanks, Ashish
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