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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Thomas Gleixner <tglx@linutronix.de>,
        Borislav Petkov <bp@suse.de>,
        Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Subject: [PATCH 4.16 097/110] x86/cpufeatures: Disentangle SSBD enumeration
Date:   Mon, 21 May 2018 23:12:34 +0200
Message-Id: <20180521210514.282653573@linuxfoundation.org>
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4.16-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Thomas Gleixner <tglx@linutronix.de>

commit 52817587e706686fcdb27f14c1b000c92f266c96 upstream

The SSBD enumeration is similarly to the other bits magically shared
between Intel and AMD though the mechanisms are different.

Make X86_FEATURE_SSBD synthetic and set it depending on the vendor specific
features or family dependent setup.

Change the Intel bit to X86_FEATURE_SPEC_CTRL_SSBD to denote that SSBD is
controlled via MSR_SPEC_CTRL and fix up the usage sites.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 arch/x86/include/asm/cpufeatures.h |    7 +++----
 arch/x86/kernel/cpu/amd.c          |    7 +------
 arch/x86/kernel/cpu/bugs.c         |   10 +++++-----
 arch/x86/kernel/cpu/common.c       |    3 +++
 arch/x86/kernel/cpu/intel.c        |    1 +
 arch/x86/kernel/process.c          |    2 +-
 6 files changed, 14 insertions(+), 16 deletions(-)

--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -207,15 +207,14 @@
 #define X86_FEATURE_INTEL_PPIN		( 7*32+14) /* Intel Processor Inventory Number */
 #define X86_FEATURE_CDP_L2		( 7*32+15) /* Code and Data Prioritization L2 */
 #define X86_FEATURE_MSR_SPEC_CTRL	( 7*32+16) /* "" MSR SPEC_CTRL is implemented */
-
+#define X86_FEATURE_SSBD		( 7*32+17) /* Speculative Store Bypass Disable */
 #define X86_FEATURE_MBA			( 7*32+18) /* Memory Bandwidth Allocation */
 #define X86_FEATURE_RSB_CTXSW		( 7*32+19) /* "" Fill RSB on context switches */
 #define X86_FEATURE_SEV			( 7*32+20) /* AMD Secure Encrypted Virtualization */
-
 #define X86_FEATURE_USE_IBPB		( 7*32+21) /* "" Indirect Branch Prediction Barrier enabled */
 #define X86_FEATURE_USE_IBRS_FW		( 7*32+22) /* "" Use IBRS during runtime firmware calls */
 #define X86_FEATURE_SPEC_STORE_BYPASS_DISABLE	( 7*32+23) /* "" Disable Speculative Store Bypass. */
-#define X86_FEATURE_AMD_SSBD		( 7*32+24)  /* "" AMD SSBD implementation */
+#define X86_FEATURE_LS_CFG_SSBD		( 7*32+24)  /* "" AMD SSBD implementation via LS_CFG MSR */
 #define X86_FEATURE_IBRS		( 7*32+25) /* Indirect Branch Restricted Speculation */
 #define X86_FEATURE_IBPB		( 7*32+26) /* Indirect Branch Prediction Barrier */
 #define X86_FEATURE_STIBP		( 7*32+27) /* Single Thread Indirect Branch Predictors */
@@ -338,7 +337,7 @@
 #define X86_FEATURE_SPEC_CTRL		(18*32+26) /* "" Speculation Control (IBRS + IBPB) */
 #define X86_FEATURE_INTEL_STIBP		(18*32+27) /* "" Single Thread Indirect Branch Predictors */
 #define X86_FEATURE_ARCH_CAPABILITIES	(18*32+29) /* IA32_ARCH_CAPABILITIES MSR (Intel) */
-#define X86_FEATURE_SSBD		(18*32+31) /* Speculative Store Bypass Disable */
+#define X86_FEATURE_SPEC_CTRL_SSBD	(18*32+31) /* "" Speculative Store Bypass Disable */
 
 /*
  * BUG word(s)
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -570,8 +570,8 @@ static void bsp_init_amd(struct cpuinfo_
 		 * avoid RMW. If that faults, do not enable SSBD.
 		 */
 		if (!rdmsrl_safe(MSR_AMD64_LS_CFG, &x86_amd_ls_cfg_base)) {
+			setup_force_cpu_cap(X86_FEATURE_LS_CFG_SSBD);
 			setup_force_cpu_cap(X86_FEATURE_SSBD);
-			setup_force_cpu_cap(X86_FEATURE_AMD_SSBD);
 			x86_amd_ls_cfg_ssbd_mask = 1ULL << bit;
 		}
 	}
@@ -919,11 +919,6 @@ static void init_amd(struct cpuinfo_x86
 	/* AMD CPUs don't reset SS attributes on SYSRET, Xen does. */
 	if (!cpu_has(c, X86_FEATURE_XENPV))
 		set_cpu_bug(c, X86_BUG_SYSRET_SS_ATTRS);
-
-	if (boot_cpu_has(X86_FEATURE_AMD_SSBD)) {
-		set_cpu_cap(c, X86_FEATURE_SSBD);
-		set_cpu_cap(c, X86_FEATURE_AMD_SSBD);
-	}
 }
 
 #ifdef CONFIG_X86_32
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -159,8 +159,8 @@ void x86_spec_ctrl_set_guest(u64 guest_s
 	if (!static_cpu_has(X86_FEATURE_MSR_SPEC_CTRL))
 		return;
 
-	/* Intel controls SSB in MSR_SPEC_CTRL */
-	if (static_cpu_has(X86_FEATURE_SPEC_CTRL))
+	/* SSBD controlled in MSR_SPEC_CTRL */
+	if (static_cpu_has(X86_FEATURE_SPEC_CTRL_SSBD))
 		host |= ssbd_tif_to_spec_ctrl(current_thread_info()->flags);
 
 	if (host != guest_spec_ctrl)
@@ -176,8 +176,8 @@ void x86_spec_ctrl_restore_host(u64 gues
 	if (!static_cpu_has(X86_FEATURE_MSR_SPEC_CTRL))
 		return;
 
-	/* Intel controls SSB in MSR_SPEC_CTRL */
-	if (static_cpu_has(X86_FEATURE_SPEC_CTRL))
+	/* SSBD controlled in MSR_SPEC_CTRL */
+	if (static_cpu_has(X86_FEATURE_SPEC_CTRL_SSBD))
 		host |= ssbd_tif_to_spec_ctrl(current_thread_info()->flags);
 
 	if (host != guest_spec_ctrl)
@@ -189,7 +189,7 @@ static void x86_amd_ssb_disable(void)
 {
 	u64 msrval = x86_amd_ls_cfg_base | x86_amd_ls_cfg_ssbd_mask;
 
-	if (boot_cpu_has(X86_FEATURE_AMD_SSBD))
+	if (boot_cpu_has(X86_FEATURE_LS_CFG_SSBD))
 		wrmsrl(MSR_AMD64_LS_CFG, msrval);
 }
 
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -767,6 +767,9 @@ static void init_speculation_control(str
 	if (cpu_has(c, X86_FEATURE_INTEL_STIBP))
 		set_cpu_cap(c, X86_FEATURE_STIBP);
 
+	if (cpu_has(c, X86_FEATURE_SPEC_CTRL_SSBD))
+		set_cpu_cap(c, X86_FEATURE_SSBD);
+
 	if (cpu_has(c, X86_FEATURE_AMD_IBRS)) {
 		set_cpu_cap(c, X86_FEATURE_IBRS);
 		set_cpu_cap(c, X86_FEATURE_MSR_SPEC_CTRL);
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -191,6 +191,7 @@ static void early_init_intel(struct cpui
 		setup_clear_cpu_cap(X86_FEATURE_MSR_SPEC_CTRL);
 		setup_clear_cpu_cap(X86_FEATURE_INTEL_STIBP);
 		setup_clear_cpu_cap(X86_FEATURE_SSBD);
+		setup_clear_cpu_cap(X86_FEATURE_SPEC_CTRL_SSBD);
 	}
 
 	/*
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -283,7 +283,7 @@ static __always_inline void __speculativ
 {
 	u64 msr;
 
-	if (static_cpu_has(X86_FEATURE_AMD_SSBD)) {
+	if (static_cpu_has(X86_FEATURE_LS_CFG_SSBD)) {
 		msr = x86_amd_ls_cfg_base | ssbd_tif_to_amd_ls_cfg(tifn);
 		wrmsrl(MSR_AMD64_LS_CFG, msr);
 	} else {