Date: Wed, 2 May 2018 08:24:59 +0000 (UTC) From: Konstantin Belousov <kib@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: r333167 - stable/11/sys/amd64/vmm Message-ID: <201805020824.w428OxpJ095242@repo.freebsd.org>
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Author: kib Date: Wed May 2 08:24:59 2018 New Revision: 333167 URL: https://svnweb.freebsd.org/changeset/base/333167 Log: MFC r332932: Correct undesirable interaction between caching of %cr4 in bhyve and invltlb_glob(). Modified: stable/11/sys/amd64/vmm/vmm_host.c Directory Properties: stable/11/ (props changed) Modified: stable/11/sys/amd64/vmm/vmm_host.c ============================================================================== --- stable/11/sys/amd64/vmm/vmm_host.c Wed May 2 08:19:06 2018 (r333166) +++ stable/11/sys/amd64/vmm/vmm_host.c Wed May 2 08:24:59 2018 (r333167) @@ -59,7 +59,16 @@ vmm_host_state_init(void) */ vmm_host_cr0 = rcr0() | CR0_TS; - vmm_host_cr4 = rcr4(); + /* + * On non-PCID or PCID but without INVPCID support machines, + * we flush kernel i.e. global TLB entries, by temporary + * clearing the CR4.PGE bit, see invltlb_glob(). If + * preemption occurs at the wrong time, cached vmm_host_cr4 + * might store the value with CR4.PGE cleared. Since FreeBSD + * requires support for PG_G on amd64, just set it + * unconditionally. + */ + vmm_host_cr4 = rcr4() | CR4_PGE; /* * Only permit a guest to use XSAVE if the host is using
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