Date: Wed, 6 Oct 2021 02:54:33 GMT From: Konstantin Belousov <kib@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: ce21d4bff1bc - main - amd64 efirt: do not flush cache for runtime pages Message-ID: <202110060254.1962sXka087660@gitrepo.freebsd.org>
next in thread | raw e-mail | index | archive | help
The branch main has been updated by kib: URL: https://cgit.FreeBSD.org/src/commit/?id=ce21d4bff1bc7e562471eeab6fb012b35029bf50 commit ce21d4bff1bc7e562471eeab6fb012b35029bf50 Author: Konstantin Belousov <kib@FreeBSD.org> AuthorDate: 2021-10-05 14:14:11 +0000 Commit: Konstantin Belousov <kib@FreeBSD.org> CommitDate: 2021-10-06 02:53:20 +0000 amd64 efirt: do not flush cache for runtime pages We actually do not know is it safe or not to flush cache for random BAR/register page existing in the system. It is well-known that for instance LAPICs cannot tolerate cache flush. As report indicates, there are more such devices. This issue typically affects AMD machines which do not report self-snoop, causing real CLFLUSH invocation on the mapped pages. Intels do self-snoop, so this change should be nop for them, and unsafe devices, if any, are already ignored. Reported and tested by: manu Reviewed by: alc, markj Sponsored by: The FreeBSD Foundation MFC after: 1 week Differential revision: https://reviews.freebsd.org/D32318 --- sys/amd64/amd64/efirt_machdep.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/sys/amd64/amd64/efirt_machdep.c b/sys/amd64/amd64/efirt_machdep.c index 6fb64816385e..6fffd113f868 100644 --- a/sys/amd64/amd64/efirt_machdep.c +++ b/sys/amd64/amd64/efirt_machdep.c @@ -254,7 +254,7 @@ efi_create_1t1_map(struct efi_md *map, int ndesc, int descsz) vm_page_init_page(m, va, -1); m->order = VM_NFREEORDER + 1; /* invalid */ m->pool = VM_NFREEPOOL + 1; /* invalid */ - pmap_page_set_memattr(m, mode); + pmap_page_set_memattr_noflush(m, mode); } } VM_OBJECT_WUNLOCK(obj_1t1_pt);
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?202110060254.1962sXka087660>