From 6ce56e1ac380eaa088d3f4c01446e15e195bd541 Mon Sep 17 00:00:00 2001
From: Laurent Dufour <ldufour@linux.ibm.com>
Date: Fri, 5 Mar 2021 13:55:54 +0100
Subject: [PATCH] powerpc/pseries: export LPAR security flavor in lparcfg
References: bsc#1188885 ltc#193722
Patch-mainline: v5.13-rc1
Git-commit: 6ce56e1ac380eaa088d3f4c01446e15e195bd541
This is helpful to read the security flavor from inside the LPAR.
In /sys/kernel/debug/powerpc/security_features it can be seen if
mitigations are on or off but not the level set through the ASMI menu.
Furthermore, reporting it through /proc/powerpc/lparcfg allows an easy
processing by the lparstat command [1].
Export it like this in /proc/powerpc/lparcfg:
$ grep security_flavor /proc/powerpc/lparcfg
security_flavor=1
Value follows what is documented on the IBM support page [2]:
0 Speculative execution fully enabled
1 Speculative execution controls to mitigate user-to-kernel attacks
2 Speculative execution controls to mitigate user-to-kernel and
user-to-user side-channel attacks
[1] https://groups.google.com/g/powerpc-utils-devel/c/NaKXvdyl_UI/m/wa2stpIDAQAJ
[2] https://www.ibm.com/support/pages/node/715841
Signed-off-by: Laurent Dufour <ldufour@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210305125554.5165-1-ldufour@linux.ibm.com
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
arch/powerpc/include/asm/hvcall.h | 1 +
arch/powerpc/platforms/pseries/lparcfg.c | 2 ++
arch/powerpc/platforms/pseries/pseries.h | 1 +
arch/powerpc/platforms/pseries/setup.c | 7 +++++++
4 files changed, 11 insertions(+)
diff --git a/arch/powerpc/include/asm/hvcall.h b/arch/powerpc/include/asm/hvcall.h
index ed6086d57b22..455e188da26d 100644
--- a/arch/powerpc/include/asm/hvcall.h
+++ b/arch/powerpc/include/asm/hvcall.h
@@ -389,6 +389,7 @@
#define H_CPU_BEHAV_FAVOUR_SECURITY (1ull << 63) // IBM bit 0
#define H_CPU_BEHAV_L1D_FLUSH_PR (1ull << 62) // IBM bit 1
#define H_CPU_BEHAV_BNDS_CHK_SPEC_BAR (1ull << 61) // IBM bit 2
+#define H_CPU_BEHAV_FAVOUR_SECURITY_H (1ull << 60) // IBM bit 3
#define H_CPU_BEHAV_FLUSH_COUNT_CACHE (1ull << 58) // IBM bit 5
#define H_CPU_BEHAV_FLUSH_LINK_STACK (1ull << 57) // IBM bit 6
diff --git a/arch/powerpc/platforms/pseries/lparcfg.c b/arch/powerpc/platforms/pseries/lparcfg.c
index e278390ab28d..f71eac74ea92 100644
--- a/arch/powerpc/platforms/pseries/lparcfg.c
+++ b/arch/powerpc/platforms/pseries/lparcfg.c
@@ -537,6 +537,8 @@ static int pseries_lparcfg_data(struct seq_file *m, void *v)
parse_em_data(m);
maxmem_data(m);
+ seq_printf(m, "security_flavor=%u\n", pseries_security_flavor);
+
return 0;
}
diff --git a/arch/powerpc/platforms/pseries/pseries.h b/arch/powerpc/platforms/pseries/pseries.h
index a13438fca10a..8925a0fac15f 100644
--- a/arch/powerpc/platforms/pseries/pseries.h
+++ b/arch/powerpc/platforms/pseries/pseries.h
@@ -108,6 +108,7 @@ static inline unsigned long cmo_get_page_size(void)
int dlpar_workqueue_init(void);
+extern u32 pseries_security_flavor;
void pseries_setup_security_mitigations(void);
void pseries_lpar_read_hblkrm_characteristics(void);
diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c
index 145e3f4c999a..754e493b7c05 100644
--- a/arch/powerpc/platforms/pseries/setup.c
+++ b/arch/powerpc/platforms/pseries/setup.c
@@ -86,6 +86,7 @@ EXPORT_SYMBOL(CMO_PageSize);
int fwnmi_active; /* TRUE if an FWNMI handler is present */
int ibm_nmi_interlock_token;
+u32 pseries_security_flavor;
static void pSeries_show_cpuinfo(struct seq_file *m)
{
@@ -535,9 +536,15 @@ static void init_cpu_char_feature_flags(struct h_cpu_char_result *result)
/*
* The features below are enabled by default, so we instead look to see
* if firmware has *disabled* them, and clear them if so.
+ * H_CPU_BEHAV_FAVOUR_SECURITY_H could be set only if
+ * H_CPU_BEHAV_FAVOUR_SECURITY is.
*/
if (!(result->behaviour & H_CPU_BEHAV_FAVOUR_SECURITY))
security_ftr_clear(SEC_FTR_FAVOUR_SECURITY);
+ else if (result->behaviour & H_CPU_BEHAV_FAVOUR_SECURITY_H)
+ pseries_security_flavor = 1;
+ else
+ pseries_security_flavor = 2;
if (!(result->behaviour & H_CPU_BEHAV_L1D_FLUSH_PR))
security_ftr_clear(SEC_FTR_L1D_FLUSH_PR);
--
2.26.2