x86/RAS/AMD: Reduce the number of IPIs when prepping error injection

We currently use wrmsr_on_cpu() 4 times when prepping for an error
injection. This will generate 4 IPIs for each MSR write. We can reduce
the number of IPIs to 1 by grouping the MSR writes and executing them
serially on the appropriate CPU.

Suggested-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Yazen Ghannam <Yazen.Ghannam@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Aravind Gopalakrishnan <aravindksg.lkml@gmail.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/1467968983-4874-3-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 28 insertions, 30 deletions

diff --git a/arch/x86/ras/mce_amd_inj.c b/arch/x86/ras/mce_amd_inj.c
index e69f4701a076..1104515d5ad2 100644
--- a/arch/x86/ras/mce_amd_inj.c
+++ b/arch/x86/ras/mce_amd_inj.c
@@ -241,6 +241,31 @@ static void toggle_nb_mca_mst_cpu(u16 nid)
                        __func__, PCI_FUNC(F3->devfn), NBCFG);
 }
 
+static void prepare_msrs(void *info)
+{
+        struct mce i_mce = *(struct mce *)info;
+        u8 b = i_mce.bank;
+
+        wrmsrl(MSR_IA32_MCG_STATUS, i_mce.mcgstatus);
+
+        if (boot_cpu_has(X86_FEATURE_SMCA)) {
+                if (i_mce.inject_flags == DFR_INT_INJ) {
+                        wrmsrl(MSR_AMD64_SMCA_MCx_DESTAT(b), i_mce.status);
+                        wrmsrl(MSR_AMD64_SMCA_MCx_DEADDR(b), i_mce.addr);
+                } else {
+                        wrmsrl(MSR_AMD64_SMCA_MCx_STATUS(b), i_mce.status);
+                        wrmsrl(MSR_AMD64_SMCA_MCx_ADDR(b), i_mce.addr);
+                }
+
+                wrmsrl(MSR_AMD64_SMCA_MCx_MISC(b), i_mce.misc);
+        } else {
+                wrmsrl(MSR_IA32_MCx_STATUS(b), i_mce.status);
+                wrmsrl(MSR_IA32_MCx_ADDR(b), i_mce.addr);
+                wrmsrl(MSR_IA32_MCx_MISC(b), i_mce.misc);
+        }
+
+}
+
 static void do_inject(void)
 {
         u64 mcg_status = 0;
@@ -287,36 +312,9 @@ static void do_inject(void)
 
         toggle_hw_mce_inject(cpu, true);
 
-        wrmsr_on_cpu(cpu, MSR_IA32_MCG_STATUS,
-                     (u32)mcg_status, (u32)(mcg_status >> 32));
-
-        if (boot_cpu_has(X86_FEATURE_SMCA)) {
-                if (inj_type == DFR_INT_INJ) {
-                        wrmsr_on_cpu(cpu, MSR_AMD64_SMCA_MCx_DESTAT(b),
-                                     (u32)i_mce.status, (u32)(i_mce.status >> 32));
-
-                        wrmsr_on_cpu(cpu, MSR_AMD64_SMCA_MCx_DEADDR(b),
-                                     (u32)i_mce.addr, (u32)(i_mce.addr >> 32));
-                } else {
-                        wrmsr_on_cpu(cpu, MSR_AMD64_SMCA_MCx_STATUS(b),
-                                     (u32)i_mce.status, (u32)(i_mce.status >> 32));
-
-                        wrmsr_on_cpu(cpu, MSR_AMD64_SMCA_MCx_ADDR(b),
-                                     (u32)i_mce.addr, (u32)(i_mce.addr >> 32));
-                }
-
-                wrmsr_on_cpu(cpu, MSR_AMD64_SMCA_MCx_MISC(b),
-                             (u32)i_mce.misc, (u32)(i_mce.misc >> 32));
-        } else {
-                wrmsr_on_cpu(cpu, MSR_IA32_MCx_STATUS(b),
-                             (u32)i_mce.status, (u32)(i_mce.status >> 32));
-
-                wrmsr_on_cpu(cpu, MSR_IA32_MCx_ADDR(b),
-                             (u32)i_mce.addr, (u32)(i_mce.addr >> 32));
-
-                wrmsr_on_cpu(cpu, MSR_IA32_MCx_MISC(b),
-                             (u32)i_mce.misc, (u32)(i_mce.misc >> 32));
-        }
+        i_mce.mcgstatus = mcg_status;
+        i_mce.inject_flags = inj_type;
+        smp_call_function_single(cpu, prepare_msrs, &i_mce, 0);
 
         toggle_hw_mce_inject(cpu, false);