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: David Woodhouse dwmw@amazon.co.uk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Srivatsa S. Bhat srivatsa@csail.mit.edu Reviewed-by: Matt Helsley (VMware) matt.helsley@gmail.com Reviewed-by: Alexey Makhalov amakhalov@vmware.com Reviewed-by: Bo Gan ganb@vmware.com ---

arch/x86/include/asm/cpufeatures.h | 6 ++++-- 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, 15 insertions(+), 14 deletions(-)

diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h index dd04cd7..7dd1bba 100644 --- a/arch/x86/include/asm/cpufeatures.h +++ b/arch/x86/include/asm/cpufeatures.h @@ -200,6 +200,7 @@ #define X86_FEATURE_RETPOLINE_AMD ( 7*32+30) /* "" AMD Retpoline mitigation for Spectre variant 2 */

#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 */

/* Because the ALTERNATIVE scheme is for members of the X86_FEATURE club... */ #define X86_FEATURE_KAISER ( 7*32+31) /* CONFIG_PAGE_TABLE_ISOLATION w/o nokaiser */ @@ -207,7 +208,8 @@ #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 */ + #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 */ @@ -306,7 +308,7 @@ #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) diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c index bd0edb2..a97fd67 100644 --- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -535,8 +535,8 @@ static void bsp_init_amd(struct cpuinfo_x86 *c) * 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; } } @@ -815,11 +815,6 @@ static void init_amd(struct cpuinfo_x86 *c) /* 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 diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index e23e289..9be7292 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -157,8 +157,8 @@ void x86_spec_ctrl_set_guest(u64 guest_spec_ctrl) 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) @@ -174,8 +174,8 @@ void x86_spec_ctrl_restore_host(u64 guest_spec_ctrl) 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) @@ -187,7 +187,7 @@ 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); }

diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 1f70ff1..1097723 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -693,6 +693,9 @@ static void init_speculation_control(struct cpuinfo_x86 *c) 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); diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c index 9a84e75..4dce22d 100644 --- a/arch/x86/kernel/cpu/intel.c +++ b/arch/x86/kernel/cpu/intel.c @@ -121,6 +121,7 @@ static void early_init_intel(struct cpuinfo_x86 *c) 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); }

/* diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index 57d4ba2..8cefbd2 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -203,7 +203,7 @@ static __always_inline void __speculative_store_bypass_update(unsigned long tifn { 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 {