git: 8934fcb4983e - releng/14.0 - amd64 pmap: Prefer consistent naming for loader tunable

The branch releng/14.0 has been updated by zlei:

URL: https://cgit.FreeBSD.org/src/commit/?id=8934fcb4983ea74fa0b741add4d8b1bd65fa0c54

commit 8934fcb4983ea74fa0b741add4d8b1bd65fa0c54
Author:     Zhenlei Huang <zlei@FreeBSD.org>
AuthorDate: 2023-10-20 07:31:44 +0000
Commit:     Zhenlei Huang <zlei@FreeBSD.org>
CommitDate: 2023-10-24 14:35:51 +0000

    amd64 pmap: Prefer consistent naming for loader tunable
    
    The sysctl knob 'vm.pmap.allow_2m_x_ept' is loader tunable and have
    public document entry in security(7) but is fetched from kernel
    environment 'hw.allow_2m_x_ept'. That is inconsistent and obscure.
    
    As there is public security advisory FreeBSD-SA-19:25.mcepsc [1],
    people may refer to it and use 'hw.allow_2m_x_ept', let's keep old
    name for compatibility.
    
    [1] https://www.freebsd.org/security/advisories/FreeBSD-SA-19:25.mcepsc.asc
    
    Reviewed by:    kib
    Approved by:    re (gjb)
    Fixes:          c08973d09c95 Workaround for Intel SKL002/SKL012S errata
    MFC after:      3 days
    Differential Revision:  https://reviews.freebsd.org/D42311
    
    (cherry picked from commit 9e7f349ff10691c2e3fb03898dbc942794a47566)
    (cherry picked from commit 8784b153a31fc0b3a12449a2f0377eb038e6fb7b)
---
 sys/amd64/amd64/pmap.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/sys/amd64/amd64/pmap.c b/sys/amd64/amd64/pmap.c
index b10997fd657b..38eab9969bb2 100644
--- a/sys/amd64/amd64/pmap.c
+++ b/sys/amd64/amd64/pmap.c
@@ -2342,7 +2342,10 @@ pmap_allow_2m_x_ept_recalculate(void)
 	    CPUID_TO_MODEL(cpu_id) == 0x57 ||	/* Knights */
 	    CPUID_TO_MODEL(cpu_id) == 0x85))))
 		pmap_allow_2m_x_ept = 1;
+#ifndef BURN_BRIDGES
 	TUNABLE_INT_FETCH("hw.allow_2m_x_ept", &pmap_allow_2m_x_ept);
+#endif
+	TUNABLE_INT_FETCH("vm.pmap.allow_2m_x_ept", &pmap_allow_2m_x_ept);
 }
 
 static bool