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powerpc/pseries: export LPAR security flavor in lparcfg

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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
This commit is contained in:
Laurent Dufour 2021-03-05 13:55:54 +01:00 committed by Michael Ellerman
parent 90cbac0e99
commit 6ce56e1ac3
4 changed files with 11 additions and 0 deletions
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1
arch/powerpc/include/asm/hvcall.h
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@ -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

2
arch/powerpc/platforms/pseries/lparcfg.c
View File

@ -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;
}

1
arch/powerpc/platforms/pseries/pseries.h
View File

@ -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);

7
arch/powerpc/platforms/pseries/setup.c
View File

@ -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);