From: Stefano Stabellini <sstabellini@kernel.org>
To: Julien Grall <julien@xen.org>
Cc: xen-devel@lists.xenproject.org, Wei.Chen@arm.com,
Henry.Wang@arm.com, Penny.Zheng@arm.com,
Bertrand.Marquis@arm.com, Julien Grall <jgrall@amazon.com>,
Stefano Stabellini <sstabellini@kernel.org>,
Volodymyr Babchuk <Volodymyr_Babchuk@epam.com>
Subject: Re: [PATCH RFCv2 13/15] xen/arm: mm: Use the PMAP helpers in xen_{,un}map_table()
Date: Fri, 14 May 2021 16:35:52 -0700 (PDT) [thread overview]
Message-ID: <alpine.DEB.2.21.2105141628130.14426@sstabellini-ThinkPad-T480s> (raw)
In-Reply-To: <20210425201318.15447-14-julien@xen.org>
On Sun, 25 Apr 2021, Julien Grall wrote:
> From: Julien Grall <jgrall@amazon.com>
>
> 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@amazon.com>
In terms of boot stages:
- SYS_STATE_early_boot --> use pmap_map
- greater than SYS_STATE_early_boot --> map_domain_page
While actually pmap would be able to work as far as SYS_STATE_boot, but
we don't need it. Is it worth simplifying it by changing the checks in
the previous patch to be against SYS_STATE_early_boot?
In any case:
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
> ---
> 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 5e713b599611..f5768f2d4a81 100644
> --- a/xen/arch/arm/mm.c
> +++ b/xen/arch/arm/mm.c
> @@ -41,6 +41,7 @@
> #include <xen/sizes.h>
> #include <xen/libfdt/libfdt.h>
>
> +#include <asm/pmap.h>
> #include <asm/setup.h>
>
> /* Override macros from asm/page.h to make them work with mfn_t */
> @@ -967,27 +968,11 @@ 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);
> }
> @@ -996,12 +981,12 @@ 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);
next prev parent reply other threads:[~2021-05-14 23:36 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-25 20:13 [PATCH RFCv2 00/15] xen/arm: mm: Remove open-coding mappings Julien Grall
2021-04-25 20:13 ` [PATCH RFCv2 01/15] xen/arm: lpae: Rename LPAE_ENTRIES_MASK_GS to LPAE_ENTRY_MASK_GS Julien Grall
2021-05-11 22:12 ` Stefano Stabellini
2021-04-25 20:13 ` [PATCH RFCv2 02/15] xen/arm: lpae: Use the generic helpers to defined the Xen PT helpers Julien Grall
2021-05-11 22:26 ` Stefano Stabellini
2021-05-12 14:26 ` Julien Grall
2021-05-12 21:30 ` Stefano Stabellini
2021-05-12 22:16 ` Julien Grall
2021-05-13 22:44 ` Stefano Stabellini
2021-07-03 17:32 ` Julien Grall
2021-07-13 20:53 ` Stefano Stabellini
2021-07-14 17:40 ` Julien Grall
2021-04-25 20:13 ` [PATCH RFCv2 03/15] xen/arm: p2m: Replace level_{orders, masks} arrays with LEVEL_{ORDER, MASK} Julien Grall
2021-05-11 22:33 ` Stefano Stabellini
2021-05-12 14:39 ` Julien Grall
2021-04-25 20:13 ` [PATCH RFCv2 04/15] xen/arm: mm: Allow other mapping size in xen_pt_update_entry() Julien Grall
2021-05-11 22:42 ` Stefano Stabellini
2021-04-25 20:13 ` [PATCH RFCv2 05/15] xen/arm: mm: Avoid flushing the TLBs when mapping are inserted Julien Grall
2021-05-11 22:51 ` Stefano Stabellini
2021-04-25 20:13 ` [PATCH RFCv2 06/15] xen/arm: mm: Don't open-code Xen PT update in remove_early_mappings() Julien Grall
2021-05-11 22:58 ` Stefano Stabellini
2021-04-25 20:13 ` [PATCH RFCv2 07/15] xen/arm: mm: Re-implement early_fdt_map() using map_pages_to_xen() Julien Grall
2021-05-12 21:41 ` Stefano Stabellini
2021-05-12 22:18 ` Julien Grall
2021-04-25 20:13 ` [PATCH RFCv2 08/15] xen/arm32: mm: Check if the virtual address is shared before updating it Julien Grall
2021-05-12 22:00 ` Stefano Stabellini
2021-05-12 22:23 ` Julien Grall
2021-05-13 22:32 ` Stefano Stabellini
2021-05-13 22:59 ` Julien Grall
2021-05-14 1:04 ` Stefano Stabellini
2021-04-25 20:13 ` [PATCH RFCv2 09/15] xen/arm32: mm: Re-implement setup_xenheap_mappings() using map_pages_to_xen() Julien Grall
2021-05-12 22:07 ` Stefano Stabellini
2021-05-13 17:55 ` Julien Grall
2021-04-25 20:13 ` [PATCH RFCv2 10/15] xen/arm: mm: Allocate xen page tables in domheap rather than xenheap Julien Grall
2021-05-12 22:44 ` Stefano Stabellini
2021-05-13 18:09 ` Julien Grall
2021-05-13 22:27 ` Stefano Stabellini
2021-05-15 8:48 ` Julien Grall
2021-05-18 0:37 ` Stefano Stabellini
2021-04-25 20:13 ` [PATCH RFCv2 11/15] xen/arm: mm: Allow page-table allocation from the boot allocator Julien Grall
2021-05-13 22:58 ` Stefano Stabellini
2021-04-25 20:13 ` [PATCH RFCv2 12/15] xen/arm: add Persistent Map (PMAP) infrastructure Julien Grall
2021-04-26 9:41 ` Xia, Hongyan
2021-07-03 17:57 ` Julien Grall
2021-04-28 21:47 ` Wei Liu
2021-05-14 23:25 ` Stefano Stabellini
2021-05-15 8:54 ` Julien Grall
2021-04-25 20:13 ` [PATCH RFCv2 13/15] xen/arm: mm: Use the PMAP helpers in xen_{,un}map_table() Julien Grall
2021-05-14 23:35 ` Stefano Stabellini [this message]
2021-05-15 9:03 ` Julien Grall
2021-04-25 20:13 ` [PATCH RFCv2 14/15] xen/arm: mm: Rework setup_xenheap_mappings() Julien Grall
2021-05-14 23:51 ` Stefano Stabellini
2021-05-15 9:21 ` Julien Grall
2021-05-18 0:50 ` Stefano Stabellini
2022-02-12 19:16 ` Julien Grall
2021-04-25 20:13 ` [PATCH RFCv2 15/15] xen/arm: mm: Re-implement setup_frame_table_mappings() with map_pages_to_xen() Julien Grall
2021-05-15 0:02 ` Stefano Stabellini
2021-05-15 9:25 ` Julien Grall
2021-05-18 0:51 ` Stefano Stabellini
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