[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [PATCH v3 16/19] xen/arm: mm: Use the PMAP helpers in xen_{,un}map_table()
On Mon, 21 Feb 2022, Julien Grall wrote: > From: Julien Grall <jgrall@xxxxxxxxxx> > > During early boot, it is not possible to use xen_{,un}map_table() > if the page tables are not residing the Xen binary. > > This is a blocker to switch some of the helpers to use xen_pt_update() > as we may need to allocate extra page tables and access them before > the domheap has been initialized (see setup_xenheap_mappings()). > > xen_{,un}map_table() are now updated to use the PMAP helpers for early > boot map/unmap. Note that the special case for page-tables residing > in Xen binary has been dropped because it is "complex" and was > only added as a workaround in 8d4f1b8878e0 ("xen/arm: mm: Allow > generic xen page-tables helpers to be called early"). > > Signed-off-by: Julien Grall <jgrall@xxxxxxxxxx> Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx> > --- > Changes in v2: > - New patch > --- > xen/arch/arm/mm.c | 33 +++++++++------------------------ > 1 file changed, 9 insertions(+), 24 deletions(-) > > diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c > index 659bdf25e0ff..11b6b60a2bc1 100644 > --- a/xen/arch/arm/mm.c > +++ b/xen/arch/arm/mm.c > @@ -25,6 +25,7 @@ > #include <xen/libfdt/libfdt.h> > #include <xen/mm.h> > #include <xen/pfn.h> > +#include <xen/pmap.h> > #include <xen/sched.h> > #include <xen/sizes.h> > #include <xen/types.h> > @@ -964,27 +965,11 @@ void *ioremap(paddr_t pa, size_t len) > static lpae_t *xen_map_table(mfn_t mfn) > { > /* > - * We may require to map the page table before map_domain_page() is > - * useable. The requirements here is it must be useable as soon as > - * page-tables are allocated dynamically via alloc_boot_pages(). > - * > - * We need to do the check on physical address rather than virtual > - * address to avoid truncation on Arm32. Therefore is_kernel() cannot > - * be used. > + * During early boot, map_domain_page() may be unusable. Use the > + * PMAP to map temporarily a page-table. > */ > if ( system_state == SYS_STATE_early_boot ) > - { > - if ( is_xen_fixed_mfn(mfn) ) > - { > - /* > - * It is fine to demote the type because the size of Xen > - * will always fit in vaddr_t. > - */ > - vaddr_t offset = mfn_to_maddr(mfn) - virt_to_maddr(&_start); > - > - return (lpae_t *)(XEN_VIRT_START + offset); > - } > - } > + return pmap_map(mfn); > > return map_domain_page(mfn); > } > @@ -993,12 +978,12 @@ static void xen_unmap_table(const lpae_t *table) > { > /* > * During early boot, xen_map_table() will not use map_domain_page() > - * for page-tables residing in Xen binary. So skip the unmap part. > + * but the PMAP. > */ > - if ( system_state == SYS_STATE_early_boot && is_kernel(table) ) > - return; > - > - unmap_domain_page(table); > + if ( system_state == SYS_STATE_early_boot ) > + pmap_unmap(table); > + else > + unmap_domain_page(table); > } > > static int create_xen_table(lpae_t *entry) > -- > 2.32.0 >
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