The following commit has been merged into the ras/core branch of tip:
Commit-ID: e48d008bd13eaa9068ff59c65275d17516179f7b
Gitweb: https://git.kernel.org/tip/e48d008bd13eaa9068ff59c65275d17516179f7b
Author: Smita Koralahalli <Smita.KoralahalliChannabasappa@xxxxxxx>
AuthorDate: Thu, 04 Nov 2021 16:58:41 -05:00
Committer: Borislav Petkov <bp@xxxxxxx>
CommitterDate: Wed, 08 Dec 2021 12:00:56 +01:00
x86/mce/inject: Check if a bank is populated before injecting
The MCA_IPID register uniquely identifies a bank's type on Scalable MCA
(SMCA) systems. When an MCA bank is not populated, the MCA_IPID register
will read as zero and writes to it will be ignored.
On a hw-type error injection (injection which writes the actual MCA
registers in an attempt to cause a real MCE) check the value of this
register before trying to inject the error.
Do not impose any limitations on a sw injection and allow the user to
test out all the decoding paths without relying on the available hardware,
as its purpose is to just test the code.
[ bp: Heavily massage. ]
Link: https://lkml.kernel.org/r/20211019233641.140275-2-Smita.KoralahalliChannabasappa@xxxxxxx
Signed-off-by: Smita Koralahalli <Smita.KoralahalliChannabasappa@xxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Link: https://lore.kernel.org/r/20211104215846.254012-2-Smita.KoralahalliChannabasappa@xxxxxxx
---
arch/x86/kernel/cpu/mce/inject.c | 42 ++++++++++++++++++++++++++++++-
1 file changed, 41 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kernel/cpu/mce/inject.c b/arch/x86/kernel/cpu/mce/inject.c
index 0bfc140..725e8e4 100644
--- a/arch/x86/kernel/cpu/mce/inject.c
+++ b/arch/x86/kernel/cpu/mce/inject.c
@@ -74,7 +74,6 @@ MCE_INJECT_SET(status);
MCE_INJECT_SET(misc);
MCE_INJECT_SET(addr);
MCE_INJECT_SET(synd);
-MCE_INJECT_SET(ipid);
#define MCE_INJECT_GET(reg) \
static int inj_##reg##_get(void *data, u64 *val) \
@@ -95,6 +94,20 @@ DEFINE_SIMPLE_ATTRIBUTE(status_fops, inj_status_get, inj_status_set, "%llx\n");
DEFINE_SIMPLE_ATTRIBUTE(misc_fops, inj_misc_get, inj_misc_set, "%llx\n");
DEFINE_SIMPLE_ATTRIBUTE(addr_fops, inj_addr_get, inj_addr_set, "%llx\n");
DEFINE_SIMPLE_ATTRIBUTE(synd_fops, inj_synd_get, inj_synd_set, "%llx\n");
+
+/* Use the user provided IPID value on a sw injection. */
+static int inj_ipid_set(void *data, u64 val)
+{
+ struct mce *m = (struct mce *)data;
+
+ if (cpu_feature_enabled(X86_FEATURE_SMCA)) {
+ if (inj_type == SW_INJ)
+ m->ipid = val;
+ }
+
+ return 0;
+}
+
DEFINE_SIMPLE_ATTRIBUTE(ipid_fops, inj_ipid_get, inj_ipid_set, "%llx\n");
static void setup_inj_struct(struct mce *m)
@@ -577,6 +590,33 @@ static int inj_bank_set(void *data, u64 val)
}
m->bank = val;
+
+ /*
+ * sw-only injection allows to write arbitrary values into the MCA
+ * registers because it tests only the decoding paths.
+ */
+ if (inj_type == SW_INJ)
+ goto inject;
+
+ /*
+ * Read IPID value to determine if a bank is populated on the target
+ * CPU.
+ */
+ if (cpu_feature_enabled(X86_FEATURE_SMCA)) {
+ u64 ipid;
+
+ if (rdmsrl_on_cpu(m->extcpu, MSR_AMD64_SMCA_MCx_IPID(val), &ipid)) {
+ pr_err("Error reading IPID on CPU%d\n", m->extcpu);
+ return -EINVAL;
+ }
+
+ if (!ipid) {
+ pr_err("Cannot inject into unpopulated bank %llu\n", val);
+ return -ENODEV;
+ }
+ }
+
+inject:
do_inject();
/* Reset injection struct */
|