6.4-stable patches

added patches:
	kvm-x86-mmu-add-never-option-to-allow-sticky-disabling-of-nx_huge_pages.patch

diff --git a/queue-6.4/kvm-x86-mmu-add-never-option-to-allow-sticky-disabling-of-nx_huge_pages.patch b/queue-6.4/kvm-x86-mmu-add-never-option-to-allow-sticky-disabling-of-nx_huge_pages.patch
new file mode 100644 (file)
index 0000000..b4a8221
--- /dev/null
+++ b/queue-6.4/kvm-x86-mmu-add-never-option-to-allow-sticky-disabling-of-nx_huge_pages.patch
@@ -0,0 +1,132 @@
+From 0b210faf337314e4bc88e796218bc70c72a51209 Mon Sep 17 00:00:00 2001
+From: Sean Christopherson <seanjc@google.com>
+Date: Thu, 1 Jun 2023 17:58:59 -0700
+Subject: KVM: x86/mmu: Add "never" option to allow sticky disabling of nx_huge_pages
+
+From: Sean Christopherson <seanjc@google.com>
+
+commit 0b210faf337314e4bc88e796218bc70c72a51209 upstream.
+
+Add a "never" option to the nx_huge_pages module param to allow userspace
+to do a one-way hard disabling of the mitigation, and don't create the
+per-VM recovery threads when the mitigation is hard disabled.  Letting
+userspace pinky swear that userspace doesn't want to enable NX mitigation
+(without reloading KVM) allows certain use cases to avoid the latency
+problems associated with spawning a kthread for each VM.
+
+E.g. in FaaS use cases, the guest kernel is trusted and the host may
+create 100+ VMs per logical CPU, which can result in 100ms+ latencies when
+a burst of VMs is created.
+
+Reported-by: Li RongQing <lirongqing@baidu.com>
+Closes: https://lore.kernel.org/all/1679555884-32544-1-git-send-email-lirongqing@baidu.com
+Cc: Yong He <zhuangel570@gmail.com>
+Cc: Robert Hoo <robert.hoo.linux@gmail.com>
+Cc: Kai Huang <kai.huang@intel.com>
+Reviewed-by: Robert Hoo <robert.hoo.linux@gmail.com>
+Acked-by: Kai Huang <kai.huang@intel.com>
+Tested-by: Luiz Capitulino <luizcap@amazon.com>
+Reviewed-by: Li RongQing <lirongqing@baidu.com>
+Link: https://lore.kernel.org/r/20230602005859.784190-1-seanjc@google.com
+Signed-off-by: Sean Christopherson <seanjc@google.com>
+Signed-off-by: Luiz Capitulino <luizcap@amazon.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ arch/x86/kvm/mmu/mmu.c |   41 ++++++++++++++++++++++++++++++++++++-----
+ 1 file changed, 36 insertions(+), 5 deletions(-)
+
+--- a/arch/x86/kvm/mmu/mmu.c
++++ b/arch/x86/kvm/mmu/mmu.c
+@@ -58,6 +58,8 @@
+ 
+ extern bool itlb_multihit_kvm_mitigation;
+ 
++static bool nx_hugepage_mitigation_hard_disabled;
++
+ int __read_mostly nx_huge_pages = -1;
+ static uint __read_mostly nx_huge_pages_recovery_period_ms;
+ #ifdef CONFIG_PREEMPT_RT
+@@ -67,12 +69,13 @@ static uint __read_mostly nx_huge_pages_
+ static uint __read_mostly nx_huge_pages_recovery_ratio = 60;
+ #endif
+ 
++static int get_nx_huge_pages(char *buffer, const struct kernel_param *kp);
+ static int set_nx_huge_pages(const char *val, const struct kernel_param *kp);
+ static int set_nx_huge_pages_recovery_param(const char *val, const struct kernel_param *kp);
+ 
+ static const struct kernel_param_ops nx_huge_pages_ops = {
+       .set = set_nx_huge_pages,
+-      .get = param_get_bool,
++      .get = get_nx_huge_pages,
+ };
+ 
+ static const struct kernel_param_ops nx_huge_pages_recovery_param_ops = {
+@@ -6844,6 +6847,14 @@ static void mmu_destroy_caches(void)
+       kmem_cache_destroy(mmu_page_header_cache);
+ }
+ 
++static int get_nx_huge_pages(char *buffer, const struct kernel_param *kp)
++{
++      if (nx_hugepage_mitigation_hard_disabled)
++              return sprintf(buffer, "never\n");
++
++      return param_get_bool(buffer, kp);
++}
++
+ static bool get_nx_auto_mode(void)
+ {
+       /* Return true when CPU has the bug, and mitigations are ON */
+@@ -6860,15 +6871,29 @@ static int set_nx_huge_pages(const char
+       bool old_val = nx_huge_pages;
+       bool new_val;
+ 
++      if (nx_hugepage_mitigation_hard_disabled)
++              return -EPERM;
++
+       /* In "auto" mode deploy workaround only if CPU has the bug. */
+-      if (sysfs_streq(val, "off"))
++      if (sysfs_streq(val, "off")) {
+               new_val = 0;
+-      else if (sysfs_streq(val, "force"))
++      } else if (sysfs_streq(val, "force")) {
+               new_val = 1;
+-      else if (sysfs_streq(val, "auto"))
++      } else if (sysfs_streq(val, "auto")) {
+               new_val = get_nx_auto_mode();
+-      else if (kstrtobool(val, &new_val) < 0)
++      } else if (sysfs_streq(val, "never")) {
++              new_val = 0;
++
++              mutex_lock(&kvm_lock);
++              if (!list_empty(&vm_list)) {
++                      mutex_unlock(&kvm_lock);
++                      return -EBUSY;
++              }
++              nx_hugepage_mitigation_hard_disabled = true;
++              mutex_unlock(&kvm_lock);
++      } else if (kstrtobool(val, &new_val) < 0) {
+               return -EINVAL;
++      }
+ 
+       __set_nx_huge_pages(new_val);
+ 
+@@ -7006,6 +7031,9 @@ static int set_nx_huge_pages_recovery_pa
+       uint old_period, new_period;
+       int err;
+ 
++      if (nx_hugepage_mitigation_hard_disabled)
++              return -EPERM;
++
+       was_recovery_enabled = calc_nx_huge_pages_recovery_period(&old_period);
+ 
+       err = param_set_uint(val, kp);
+@@ -7164,6 +7192,9 @@ int kvm_mmu_post_init_vm(struct kvm *kvm
+ {
+       int err;
+ 
++      if (nx_hugepage_mitigation_hard_disabled)
++              return 0;
++
+       err = kvm_vm_create_worker_thread(kvm, kvm_nx_huge_page_recovery_worker, 0,
+                                         "kvm-nx-lpage-recovery",
+                                         &kvm->arch.nx_huge_page_recovery_thread);

diff --git a/queue-6.4/series b/queue-6.4/series
index a6850f43ca00d7c57b6ac6ba8a11ffe290628e9e..e9ea84630e5d2dd0aeb958463684d752be659dcf 100644 (file)
--- a/queue-6.4/series
+++ b/queue-6.4/series
@@ -86,3 +86,4 @@ platform-mellanox-fix-mlxbf-tmfifo-not-handling-all-.patch
 sbitmap-fix-batching-wakeup.patch
 cpufreq-intel_pstate-set-stale-cpu-frequency-to-minimum.patch
 tpm-enable-hwrng-only-for-pluton-on-amd-cpus.patch
+kvm-x86-mmu-add-never-option-to-allow-sticky-disabling-of-nx_huge_pages.patch