[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [PATCH v2 1/5] x86/shim: map and unmap page tables in replace_va_mapping
On Thu, 2020-04-09 at 11:42 +0200, Jan Beulich wrote: > On 08.04.2020 15:36, Hongyan Xia wrote: > > --- a/xen/arch/x86/pv/shim.c > > +++ b/xen/arch/x86/pv/shim.c > > @@ -168,16 +168,17 @@ const struct platform_bad_page *__init > > pv_shim_reserved_pages(unsigned int *size > > static void __init replace_va_mapping(struct domain *d, > > l4_pgentry_t *l4start, > > unsigned long va, mfn_t mfn) > > { > > - l4_pgentry_t *pl4e = l4start + l4_table_offset(va); > > - l3_pgentry_t *pl3e = l4e_to_l3e(*pl4e) + l3_table_offset(va); > > - l2_pgentry_t *pl2e = l3e_to_l2e(*pl3e) + l2_table_offset(va); > > - l1_pgentry_t *pl1e = l2e_to_l1e(*pl2e) + l1_table_offset(va); > > + l4_pgentry_t l4e = l4start[l4_table_offset(va)]; > > + l3_pgentry_t l3e = l3e_from_l4e(l4e, l3_table_offset(va)); > > + l2_pgentry_t l2e = l2e_from_l3e(l3e, l2_table_offset(va)); > > + l1_pgentry_t *pl1e = map_l1t_from_l2e(l2e) + > > l1_table_offset(va); > > struct page_info *page = mfn_to_page(l1e_get_mfn(*pl1e)); > > > > put_page_and_type(page); > > > > *pl1e = l1e_from_mfn(mfn, (!is_pv_32bit_domain(d) ? L1_PROT > > : > > COMPAT_L1_PROT)); > > + UNMAP_DOMAIN_PAGE(pl1e); > > } > > As said before, here and below I think it should be > unmap_domain_page(). > > > --- a/xen/include/asm-x86/page.h > > +++ b/xen/include/asm-x86/page.h > > @@ -196,6 +196,19 @@ static inline l4_pgentry_t > > l4e_from_paddr(paddr_t pa, unsigned int flags) > > #define map_l2t_from_l3e(x) (l2_pgentry_t > > *)map_domain_page(l3e_get_mfn(x)) > > #define map_l3t_from_l4e(x) (l3_pgentry_t > > *)map_domain_page(l4e_get_mfn(x)) > > > > +/* Unlike lYe_to_lXe(), lXe_from_lYe() do not rely on the direct > > map. */ > > +#define l2e_from_l3e(l3e, offset) ({ \ > > + const l2_pgentry_t *l2t = map_l2t_from_l3e(l3e); \ > > + l2_pgentry_t l2e = l2t[offset]; \ > > + UNMAP_DOMAIN_PAGE(l2t); \ > > + l2e; }) > > + > > +#define l3e_from_l4e(l4e, offset) ({ \ > > + const l3_pgentry_t *l3t = map_l3t_from_l4e(l4e); \ > > + l3_pgentry_t l3e = l3t[offset]; \ > > + UNMAP_DOMAIN_PAGE(l3t); \ > > + l3e; }) > > I think l1e_from_l2e() should be introduced at the same time, even > if for now it's unused. I also think, like we do elsewhere, that > macro-local variables would better have _ suffixes, to avoid > possible variable aliasing issues. Shall I address the comments and send a new rev now, or is this small series still being reviewed? Hongyan
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