Enable xstate supervisor support for User Interrupts by default.
The user interrupt state for a task consists of the MSR state and the User Interrupt Flag (UIF) value. XSAVES and XRSTORS handle saving and restoring both of these states.
<The supervisor XSTATE code might be reworked based on issues reported in the past. The Uintr context switching code would also need rework and additional testing in that regard.>
Signed-off-by: Sohil Mehta sohil.mehta@intel.com --- arch/x86/include/asm/fpu/types.h | 20 +++++++++++++++++++- arch/x86/include/asm/fpu/xstate.h | 3 ++- arch/x86/kernel/cpu/common.c | 6 ++++++ arch/x86/kernel/fpu/xstate.c | 20 +++++++++++++++++--- 4 files changed, 44 insertions(+), 5 deletions(-)
diff --git a/arch/x86/include/asm/fpu/types.h b/arch/x86/include/asm/fpu/types.h index f5a38a5f3ae1..b614f1416bea 100644 --- a/arch/x86/include/asm/fpu/types.h +++ b/arch/x86/include/asm/fpu/types.h @@ -118,7 +118,7 @@ enum xfeature { XFEATURE_RSRVD_COMP_11, XFEATURE_RSRVD_COMP_12, XFEATURE_RSRVD_COMP_13, - XFEATURE_RSRVD_COMP_14, + XFEATURE_UINTR, XFEATURE_LBR,
XFEATURE_MAX, @@ -135,6 +135,7 @@ enum xfeature { #define XFEATURE_MASK_PT (1 << XFEATURE_PT_UNIMPLEMENTED_SO_FAR) #define XFEATURE_MASK_PKRU (1 << XFEATURE_PKRU) #define XFEATURE_MASK_PASID (1 << XFEATURE_PASID) +#define XFEATURE_MASK_UINTR (1 << XFEATURE_UINTR) #define XFEATURE_MASK_LBR (1 << XFEATURE_LBR)
#define XFEATURE_MASK_FPSSE (XFEATURE_MASK_FP | XFEATURE_MASK_SSE) @@ -237,6 +238,23 @@ struct pkru_state { u32 pad; } __packed;
+/* + * State component 14 is supervisor state used for User Interrupts state. + * The size of this state is 48 bytes + */ +struct uintr_state { + u64 handler; + u64 stack_adjust; + u32 uitt_size; + u8 uinv; + u8 pad1; + u8 pad2; + u8 uif_pad3; /* bit 7 - UIF, bits 6:0 - reserved */ + u64 upid_addr; + u64 uirr; + u64 uitt_addr; +} __packed; + /* * State component 15: Architectural LBR configuration state. * The size of Arch LBR state depends on the number of LBRs (lbr_depth). diff --git a/arch/x86/include/asm/fpu/xstate.h b/arch/x86/include/asm/fpu/xstate.h index 109dfcc75299..4dd4e83c0c9d 100644 --- a/arch/x86/include/asm/fpu/xstate.h +++ b/arch/x86/include/asm/fpu/xstate.h @@ -44,7 +44,8 @@ (XFEATURE_MASK_USER_SUPPORTED & ~XFEATURE_MASK_PKRU)
/* All currently supported supervisor features */ -#define XFEATURE_MASK_SUPERVISOR_SUPPORTED (XFEATURE_MASK_PASID) +#define XFEATURE_MASK_SUPERVISOR_SUPPORTED (XFEATURE_MASK_PASID | \ + XFEATURE_MASK_UINTR)
/* * A supervisor state component may not always contain valuable information, diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 55fee930b6d1..3a0a3f5cfe0f 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -334,6 +334,12 @@ static __always_inline void setup_uintr(struct cpuinfo_x86 *c) if (!cpu_has(c, X86_FEATURE_UINTR)) goto disable_uintr;
+ /* Confirm XSAVE support for UINTR is present. */ + if (!cpu_has_xfeatures(XFEATURE_MASK_UINTR, NULL)) { + pr_info_once("x86: User Interrupts (UINTR) not enabled. XSAVE support for UINTR is missing.\n"); + goto clear_uintr_cap; + } + /* * User Interrupts currently doesn't support PTI. For processors that * support User interrupts PTI in auto mode will default to off. Need diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index c8def1b7f8fb..ab19403effb0 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -38,6 +38,10 @@ static const char *xfeature_names[] = "Processor Trace (unused)" , "Protection Keys User registers", "PASID state", + "unknown xstate feature 11", + "unknown xstate feature 12", + "unknown xstate feature 13", + "User Interrupts registers", "unknown xstate feature" , };
@@ -53,6 +57,10 @@ static short xsave_cpuid_features[] __initdata = { X86_FEATURE_INTEL_PT, X86_FEATURE_PKU, X86_FEATURE_ENQCMD, + -1, /* Unknown 11 */ + -1, /* Unknown 12 */ + -1, /* Unknown 13 */ + X86_FEATURE_UINTR, };
/* @@ -236,6 +244,7 @@ static void __init print_xstate_features(void) print_xstate_feature(XFEATURE_MASK_Hi16_ZMM); print_xstate_feature(XFEATURE_MASK_PKRU); print_xstate_feature(XFEATURE_MASK_PASID); + print_xstate_feature(XFEATURE_MASK_UINTR); }
/* @@ -372,7 +381,8 @@ static void __init print_xstate_offset_size(void) XFEATURE_MASK_PKRU | \ XFEATURE_MASK_BNDREGS | \ XFEATURE_MASK_BNDCSR | \ - XFEATURE_MASK_PASID) + XFEATURE_MASK_PASID | \ + XFEATURE_MASK_UINTR)
/* * setup the xstate image representing the init state @@ -532,6 +542,7 @@ static void check_xstate_against_struct(int nr) XCHECK_SZ(sz, nr, XFEATURE_Hi16_ZMM, struct avx_512_hi16_state); XCHECK_SZ(sz, nr, XFEATURE_PKRU, struct pkru_state); XCHECK_SZ(sz, nr, XFEATURE_PASID, struct ia32_pasid_state); + XCHECK_SZ(sz, nr, XFEATURE_UINTR, struct uintr_state);
/* * Make *SURE* to add any feature numbers in below if @@ -539,9 +550,12 @@ static void check_xstate_against_struct(int nr) * numbers. */ if ((nr < XFEATURE_YMM) || - (nr >= XFEATURE_MAX) || (nr == XFEATURE_PT_UNIMPLEMENTED_SO_FAR) || - ((nr >= XFEATURE_RSRVD_COMP_11) && (nr <= XFEATURE_LBR))) { + (nr == XFEATURE_RSRVD_COMP_11) || + (nr == XFEATURE_RSRVD_COMP_12) || + (nr == XFEATURE_RSRVD_COMP_13) || + (nr == XFEATURE_LBR) || + (nr >= XFEATURE_MAX)) { WARN_ONCE(1, "no structure for xstate: %d\n", nr); XSTATE_WARN_ON(1); }