Date: Thu, 18 Aug 2016 09:29:35 +0000 (UTC) From: Alexander Motin <mav@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-11@freebsd.org Subject: svn commit: r304363 - stable/11/sys/dev/ntb/ntb_hw Message-ID: <201608180929.u7I9TZph094459@repo.freebsd.org>
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Author: mav Date: Thu Aug 18 09:29:35 2016 New Revision: 304363 URL: https://svnweb.freebsd.org/changeset/base/304363 Log: MFC r302531: Revert odd change, setting limit registers before base. I don't know what errata is mentioned there, I was unable to find it, but setting limit before the base simply does not work at all. According to specification attempt to set limit out of the present window range resets it to zero, effectively disabling it. And that is what I see in practice. Fixing this properly disables access for remote side to our memory until respective xlat is negotiated and set. As I see, Linux does the same. Modified: stable/11/sys/dev/ntb/ntb_hw/ntb_hw.c Directory Properties: stable/11/ (props changed) Modified: stable/11/sys/dev/ntb/ntb_hw/ntb_hw.c ============================================================================== --- stable/11/sys/dev/ntb/ntb_hw/ntb_hw.c Thu Aug 18 09:28:59 2016 (r304362) +++ stable/11/sys/dev/ntb/ntb_hw/ntb_hw.c Thu Aug 18 09:29:35 2016 (r304363) @@ -1699,26 +1699,22 @@ xeon_set_sbar_base_and_limit(struct ntb_ bar_addr = 0; } - /* - * Set limit registers first to avoid an errata where setting the base - * registers locks the limit registers. - */ if (!bar_is_64bit(ntb, idx)) { - ntb_reg_write(4, lmt_reg, bar_addr); - reg_val = ntb_reg_read(4, lmt_reg); - (void)reg_val; - ntb_reg_write(4, base_reg, bar_addr); reg_val = ntb_reg_read(4, base_reg); (void)reg_val; - } else { - ntb_reg_write(8, lmt_reg, bar_addr); - reg_val = ntb_reg_read(8, lmt_reg); - (void)reg_val; + ntb_reg_write(4, lmt_reg, bar_addr); + reg_val = ntb_reg_read(4, lmt_reg); + (void)reg_val; + } else { ntb_reg_write(8, base_reg, bar_addr); reg_val = ntb_reg_read(8, base_reg); (void)reg_val; + + ntb_reg_write(8, lmt_reg, bar_addr); + reg_val = ntb_reg_read(8, lmt_reg); + (void)reg_val; } }
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