FAILED: patch "[PATCH] x86/mm: Avoid incomplete Global INVLPG flushes" failed to apply to 5.15-stable tree

* FAILED: patch "[PATCH] x86/mm: Avoid incomplete Global INVLPG flushes" failed to apply to 5.15-stable tree
@ 2023-05-26 19:27 gregkh
  2023-05-27  0:18 ` [PATCH 5.15.y] x86/mm: Avoid incomplete Global INVLPG flushes Daniel Sneddon
  0 siblings, 1 reply; 3+ messages in thread
From: gregkh @ 2023-05-26 19:27 UTC (permalink / raw)
  To: dave.hansen, tglx; +Cc: stable


The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x ce0b15d11ad837fbacc5356941712218e38a0a83
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2023052612-reproach-snowbird-d3a2@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:

ce0b15d11ad8 ("x86/mm: Avoid incomplete Global INVLPG flushes")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From ce0b15d11ad837fbacc5356941712218e38a0a83 Mon Sep 17 00:00:00 2001
From: Dave Hansen <dave.hansen@linux.intel.com>
Date: Tue, 16 May 2023 12:24:25 -0700
Subject: [PATCH] x86/mm: Avoid incomplete Global INVLPG flushes

The INVLPG instruction is used to invalidate TLB entries for a
specified virtual address.  When PCIDs are enabled, INVLPG is supposed
to invalidate TLB entries for the specified address for both the
current PCID *and* Global entries.  (Note: Only kernel mappings set
Global=1.)

Unfortunately, some INVLPG implementations can leave Global
translations unflushed when PCIDs are enabled.

As a workaround, never enable PCIDs on affected processors.

I expect there to eventually be microcode mitigations to replace this
software workaround.  However, the exact version numbers where that
will happen are not known today.  Once the version numbers are set in
stone, the processor list can be tweaked to only disable PCIDs on
affected processors with affected microcode.

Note: if anyone wants a quick fix that doesn't require patching, just
stick 'nopcid' on your kernel command-line.

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org

diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index 3cdac0f0055d..8192452d1d2d 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -9,6 +9,7 @@
 #include <linux/sched/task.h>
 
 #include <asm/set_memory.h>
+#include <asm/cpu_device_id.h>
 #include <asm/e820/api.h>
 #include <asm/init.h>
 #include <asm/page.h>
@@ -261,6 +262,24 @@ static void __init probe_page_size_mask(void)
 	}
 }
 
+#define INTEL_MATCH(_model) { .vendor  = X86_VENDOR_INTEL,	\
+			      .family  = 6,			\
+			      .model = _model,			\
+			    }
+/*
+ * INVLPG may not properly flush Global entries
+ * on these CPUs when PCIDs are enabled.
+ */
+static const struct x86_cpu_id invlpg_miss_ids[] = {
+	INTEL_MATCH(INTEL_FAM6_ALDERLAKE   ),
+	INTEL_MATCH(INTEL_FAM6_ALDERLAKE_L ),
+	INTEL_MATCH(INTEL_FAM6_ALDERLAKE_N ),
+	INTEL_MATCH(INTEL_FAM6_RAPTORLAKE  ),
+	INTEL_MATCH(INTEL_FAM6_RAPTORLAKE_P),
+	INTEL_MATCH(INTEL_FAM6_RAPTORLAKE_S),
+	{}
+};
+
 static void setup_pcid(void)
 {
 	if (!IS_ENABLED(CONFIG_X86_64))
@@ -269,6 +288,12 @@ static void setup_pcid(void)
 	if (!boot_cpu_has(X86_FEATURE_PCID))
 		return;
 
+	if (x86_match_cpu(invlpg_miss_ids)) {
+		pr_info("Incomplete global flushes, disabling PCID");
+		setup_clear_cpu_cap(X86_FEATURE_PCID);
+		return;
+	}
+
 	if (boot_cpu_has(X86_FEATURE_PGE)) {
 		/*
 		 * This can't be cr4_set_bits_and_update_boot() -- the


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