4 files changed, 25 insertions, 9 deletions

diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h
index c936ce9f0c47..dfdb103ae4f6 100644
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -321,7 +321,7 @@ static inline void indirect_branch_prediction_barrier(void)
 /* The Intel SPEC CTRL MSR base value cache */
 extern u64 x86_spec_ctrl_base;
 DECLARE_PER_CPU(u64, x86_spec_ctrl_current);
-extern void write_spec_ctrl_current(u64 val, bool force);
+extern void update_spec_ctrl_cond(u64 val);
 extern u64 spec_ctrl_current(void);
 
 /*
diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index 5059799bebe3..286a71810f9e 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -139,6 +139,7 @@ static inline int pmd_dirty(pmd_t pmd)
 	return pmd_flags(pmd) & _PAGE_DIRTY;
 }
 
+#define pmd_young pmd_young
 static inline int pmd_young(pmd_t pmd)
 {
 	return pmd_flags(pmd) & _PAGE_ACCESSED;
@@ -1438,6 +1439,14 @@ static inline bool arch_has_hw_pte_young(void)
 	return true;
 }
 
+#ifdef CONFIG_XEN_PV
+#define arch_has_hw_nonleaf_pmd_young arch_has_hw_nonleaf_pmd_young
+static inline bool arch_has_hw_nonleaf_pmd_young(void)
+{
+	return !cpu_feature_enabled(X86_FEATURE_XENPV);
+}
+#endif
+
 #ifdef CONFIG_PAGE_TABLE_CHECK
 static inline bool pte_user_accessible_page(pte_t pte)
 {
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index 3e3230cccaa7..6daf84229548 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -60,11 +60,18 @@ EXPORT_SYMBOL_GPL(x86_spec_ctrl_current);
 
 static DEFINE_MUTEX(spec_ctrl_mutex);
 
+/* Update SPEC_CTRL MSR and its cached copy unconditionally */
+static void update_spec_ctrl(u64 val)
+{
+	this_cpu_write(x86_spec_ctrl_current, val);
+	wrmsrl(MSR_IA32_SPEC_CTRL, val);
+}
+
 /*
  * Keep track of the SPEC_CTRL MSR value for the current task, which may differ
  * from x86_spec_ctrl_base due to STIBP/SSB in __speculation_ctrl_update().
  */
-void write_spec_ctrl_current(u64 val, bool force)
+void update_spec_ctrl_cond(u64 val)
 {
 	if (this_cpu_read(x86_spec_ctrl_current) == val)
 		return;
@@ -75,7 +82,7 @@ void write_spec_ctrl_current(u64 val, bool force)
 	 * When KERNEL_IBRS this MSR is written on return-to-user, unless
 	 * forced the update can be delayed until that time.
 	 */
-	if (force || !cpu_feature_enabled(X86_FEATURE_KERNEL_IBRS))
+	if (!cpu_feature_enabled(X86_FEATURE_KERNEL_IBRS))
 		wrmsrl(MSR_IA32_SPEC_CTRL, val);
 }
 
@@ -1328,7 +1335,7 @@ static void __init spec_ctrl_disable_kernel_rrsba(void)
 
 	if (ia32_cap & ARCH_CAP_RRSBA) {
 		x86_spec_ctrl_base |= SPEC_CTRL_RRSBA_DIS_S;
-		write_spec_ctrl_current(x86_spec_ctrl_base, true);
+		update_spec_ctrl(x86_spec_ctrl_base);
 	}
 }
 
@@ -1450,7 +1457,7 @@ static void __init spectre_v2_select_mitigation(void)
 
 	if (spectre_v2_in_ibrs_mode(mode)) {
 		x86_spec_ctrl_base |= SPEC_CTRL_IBRS;
-		write_spec_ctrl_current(x86_spec_ctrl_base, true);
+		update_spec_ctrl(x86_spec_ctrl_base);
 	}
 
 	switch (mode) {
@@ -1564,7 +1571,7 @@ static void __init spectre_v2_select_mitigation(void)
 static void update_stibp_msr(void * __unused)
 {
 	u64 val = spec_ctrl_current() | (x86_spec_ctrl_base & SPEC_CTRL_STIBP);
-	write_spec_ctrl_current(val, true);
+	update_spec_ctrl(val);
 }
 
 /* Update x86_spec_ctrl_base in case SMT state changed. */
@@ -1797,7 +1804,7 @@ static enum ssb_mitigation __init __ssb_select_mitigation(void)
 			x86_amd_ssb_disable();
 		} else {
 			x86_spec_ctrl_base |= SPEC_CTRL_SSBD;
-			write_spec_ctrl_current(x86_spec_ctrl_base, true);
+			update_spec_ctrl(x86_spec_ctrl_base);
 		}
 	}
 
@@ -2048,7 +2055,7 @@ int arch_prctl_spec_ctrl_get(struct task_struct *task, unsigned long which)
 void x86_spec_ctrl_setup_ap(void)
 {
 	if (boot_cpu_has(X86_FEATURE_MSR_SPEC_CTRL))
-		write_spec_ctrl_current(x86_spec_ctrl_base, true);
+		update_spec_ctrl(x86_spec_ctrl_base);
 
 	if (ssb_mode == SPEC_STORE_BYPASS_DISABLE)
 		x86_amd_ssb_disable();
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index c21b7347a26d..e436c9c1ef3b 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -600,7 +600,7 @@ static __always_inline void __speculation_ctrl_update(unsigned long tifp,
 	}
 
 	if (updmsr)
-		write_spec_ctrl_current(msr, false);
+		update_spec_ctrl_cond(msr);
 }
 
 static unsigned long speculation_ctrl_update_tif(struct task_struct *tsk)