kernel/linux.git/drivers/xen/gntdev.c, branch v5.15.7

Xen/gntdev: don't ignore kernel unmapping error

2021-09-20T14:57:08+00:00

While working on XSA-361 and its follow-ups, I failed to spot another place where the kernel mapping part of an operation was not treated the same as the user space part. Detect and propagate errors and add a 2nd pr_debug(). Signed-off-by: Jan Beulich Reviewed-by: Juergen Gross Link: https://lore.kernel.org/r/c2513395-74dc-aea3-9192-fd265aa44e35@suse.com Signed-off-by: Juergen Gross

xen: assume XENFEAT_gnttab_map_avail_bits being set for pv guests

2021-08-30T09:57:50+00:00

XENFEAT_gnttab_map_avail_bits is always set in Xen 4.0 and newer. Remove coding assuming it might be zero. Signed-off-by: Juergen Gross Acked-by: Peter Zijlstra (Intel) Reviewed-by: Boris Ostrovsky Link: https://lore.kernel.org/r/20210730071804.4302-4-jgross@suse.com Signed-off-by: Juergen Gross

xen/gntdev: fix gntdev_mmap() error exit path

2021-05-10T07:32:00+00:00

Commit d3eeb1d77c5d0af ("xen/gntdev: use mmu_interval_notifier_insert") introduced an error in gntdev_mmap(): in case the call of mmu_interval_notifier_insert_locked() fails the exit path should not call mmu_interval_notifier_remove(), as this might result in NULL dereferences. One reason for failure is e.g. a signal pending for the running process. Fixes: d3eeb1d77c5d0af ("xen/gntdev: use mmu_interval_notifier_insert") Cc: stable@vger.kernel.org Reported-by: Marek Marczykowski-Górecki Tested-by: Marek Marczykowski-Górecki Signed-off-by: Juergen Gross Reviewed-by: Luca Fancellu Link: https://lore.kernel.org/r/20210423054038.26696-1-jgross@suse.com Signed-off-by: Juergen Gross

Xen/gntdev: don't needlessly use kvcalloc()

2021-03-10T22:39:29+00:00

Requesting zeroed memory when all of it will be overwritten subsequently by all ones is a waste of processing bandwidth. In fact, rather than recording zeroed ->grants[], fill that array too with more appropriate "invalid" indicators. Signed-off-by: Jan Beulich Reviewed-by: Juergen Gross Link: https://lore.kernel.org/r/9a726be2-4893-8ffe-0ef1-b70dd1c229b1@suse.com Signed-off-by: Boris Ostrovsky

Xen/gnttab: introduce common INVALID_GRANT_{HANDLE,REF}

2021-03-10T22:39:29+00:00

It's not helpful if every driver has to cook its own. Generalize xenbus'es INVALID_GRANT_HANDLE and pcifront's INVALID_GRANT_REF (which shouldn't have expanded to zero to begin with). Use the constants in p2m.c and gntdev.c right away, and update field types where necessary so they would match with the constants' types (albeit without touching struct ioctl_gntdev_grant_ref's ref field, as that's part of the public interface of the kernel and would require introducing a dependency on Xen's grant_table.h public header). Signed-off-by: Jan Beulich Reviewed-by: Juergen Gross Link: https://lore.kernel.org/r/db7c38a5-0d75-d5d1-19de-e5fe9f0b9c48@suse.com Signed-off-by: Boris Ostrovsky

Xen/gntdev: don't needlessly allocate k{,un}map_ops[]

2021-03-10T22:39:29+00:00

They're needed only in the not-auto-translate (i.e. PV) case; there's no point in allocating memory that's never going to get accessed. Signed-off-by: Jan Beulich Reviewed-by: Juergen Gross Link: https://lore.kernel.org/r/180d50cb-5531-8952-4bf0-d65c554638ed@suse.com Signed-off-by: Boris Ostrovsky

Xen/gntdev: correct error checking in gntdev_map_grant_pages()

2021-02-15T07:52:27+00:00

Failure of the kernel part of the mapping operation should also be indicated as an error to the caller, or else it may assume the respective kernel VA is okay to access. Furthermore gnttab_map_refs() failing still requires recording successfully mapped handles, so they can be unmapped subsequently. This in turn requires there to be a way to tell full hypercall failure from partial success - preset map_op status fields such that they won't "happen" to look as if the operation succeeded. Also again use GNTST_okay instead of implying its value (zero). This is part of XSA-361. Signed-off-by: Jan Beulich Cc: stable@vger.kernel.org Reviewed-by: Juergen Gross Signed-off-by: Juergen Gross

Xen/gntdev: correct dev_bus_addr handling in gntdev_map_grant_pages()

2021-02-15T07:51:07+00:00

We may not skip setting the field in the unmap structure when GNTMAP_device_map is in use - such an unmap would fail to release the respective resources (a page ref in the hypervisor). Otoh the field doesn't need setting at all when GNTMAP_device_map is not in use. To record the value for unmapping, we also better don't use our local p2m: In particular after a subsequent change it may not have got updated for all the batch elements. Instead it can simply be taken from the respective map's results. We can additionally avoid playing this game altogether for the kernel part of the mappings in (x86) PV mode. This is part of XSA-361. Signed-off-by: Jan Beulich Cc: stable@vger.kernel.org Reviewed-by: Stefano Stabellini Signed-off-by: Juergen Gross

xen/gntdev.c: Convert get_user_pages() to pin_user_pages()

2020-10-04T23:41:33+00:00

In 2019, we introduced pin_user_pages*() and now we are converting get_user_pages*() to the new API as appropriate. [1] & [2] could be referred for more information. This is case 5 as per document [1]. [1] Documentation/core-api/pin_user_pages.rst [2] "Explicit pinning of user-space pages": https://lwn.net/Articles/807108/ Signed-off-by: Souptick Joarder Cc: John Hubbard Cc: Boris Ostrovsky Cc: Juergen Gross Cc: David Vrabel Link: https://lore.kernel.org/r/1599375114-32360-2-git-send-email-jrdr.linux@gmail.com Reviewed-by: Boris Ostrovsky Signed-off-by: Boris Ostrovsky

xen/gntdev.c: Mark pages as dirty

2020-10-04T23:39:18+00:00

There seems to be a bug in the original code when gntdev_get_page() is called with writeable=true then the page needs to be marked dirty before being put. To address this, a bool writeable is added in gnt_dev_copy_batch, set it in gntdev_grant_copy_seg() (and drop `writeable` argument to gntdev_get_page()) and then, based on batch->writeable, use set_page_dirty_lock(). Fixes: a4cdb556cae0 (xen/gntdev: add ioctl for grant copy) Suggested-by: Boris Ostrovsky Signed-off-by: Souptick Joarder Cc: John Hubbard Cc: Boris Ostrovsky Cc: Juergen Gross Cc: David Vrabel Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/1599375114-32360-1-git-send-email-jrdr.linux@gmail.com Reviewed-by: Boris Ostrovsky Signed-off-by: Boris Ostrovsky

kernel/linux.git/drivers/xen/gntdev.c, branch v5.15.7

Xen/gntdev: don't ignore kernel unmapping error

xen: assume XENFEAT_gnttab_map_avail_bits being set for pv guests

xen/gntdev: fix gntdev_mmap() error exit path

Xen/gntdev: don't needlessly use kvcalloc()

Xen/gnttab: introduce common INVALID_GRANT_{HANDLE,REF}

Xen/gntdev: don't needlessly allocate k{,un}map_ops[]

Xen/gntdev: correct error checking in gntdev_map_grant_pages()

Xen/gntdev: correct dev_bus_addr handling in gntdev_map_grant_pages()

xen/gntdev.c: Convert get_user_pages*() to pin_user_pages*()

xen/gntdev.c: Mark pages as dirty

xen/gntdev.c: Convert get_user_pages() to pin_user_pages()