The following commit has been merged into the x86/fpu branch of tip: Commit-ID: 126fe0401883598b45b34dbbd5e0d7d8a0aefa21 Gitweb: https://git.kernel.org/tip/126fe0401883598b45b34dbbd5e0d7d8a0aefa21 Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx> AuthorDate: Fri, 15 Oct 2021 03:16:07 +02:00 Committer: Borislav Petkov <bp@xxxxxxx> CommitterDate: Wed, 20 Oct 2021 15:27:26 +02:00 x86/fpu: Cleanup xstate xcomp_bv initialization No point in having this duplicated all over the place with needlessly different defines. Provide a proper initialization function which initializes user buffers properly and make KVM use it. Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Signed-off-by: Borislav Petkov <bp@xxxxxxx> Link: https://lkml.kernel.org/r/20211015011538.897664678@xxxxxxxxxxxxx --- arch/x86/include/asm/fpu/internal.h | 4 ++- arch/x86/kernel/fpu/core.c | 35 +++++++++++++++------------- arch/x86/kernel/fpu/init.c | 6 ++--- arch/x86/kernel/fpu/xstate.c | 8 ++---- arch/x86/kernel/fpu/xstate.h | 18 ++++++++++++++- arch/x86/kvm/x86.c | 11 ++------- 6 files changed, 49 insertions(+), 33 deletions(-) create mode 100644 arch/x86/kernel/fpu/xstate.h diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h index 1503750..df57f1a 100644 --- a/arch/x86/include/asm/fpu/internal.h +++ b/arch/x86/include/asm/fpu/internal.h @@ -80,7 +80,9 @@ static __always_inline __pure bool use_fxsr(void) extern union fpregs_state init_fpstate; -extern void fpstate_init(union fpregs_state *state); +extern void fpstate_init_user(union fpregs_state *state); +extern void fpu_init_fpstate_user(struct fpu *fpu); + #ifdef CONFIG_MATH_EMULATION extern void fpstate_init_soft(struct swregs_state *soft); #else diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c index 9a6b195..0789f0c 100644 --- a/arch/x86/kernel/fpu/core.c +++ b/arch/x86/kernel/fpu/core.c @@ -16,6 +16,8 @@ #include <linux/hardirq.h> #include <linux/pkeys.h> +#include "xstate.h" + #define CREATE_TRACE_POINTS #include <asm/trace/fpu.h> @@ -203,15 +205,6 @@ void fpu_sync_fpstate(struct fpu *fpu) fpregs_unlock(); } -static inline void fpstate_init_xstate(struct xregs_state *xsave) -{ - /* - * XRSTORS requires these bits set in xcomp_bv, or it will - * trigger #GP: - */ - xsave->header.xcomp_bv = XCOMP_BV_COMPACTED_FORMAT | xfeatures_mask_all; -} - static inline unsigned int init_fpstate_copy_size(void) { if (!use_xsave()) @@ -238,23 +231,33 @@ static inline void fpstate_init_fstate(struct fregs_state *fp) fp->fos = 0xffff0000u; } -void fpstate_init(union fpregs_state *state) +/* + * Used in two places: + * 1) Early boot to setup init_fpstate for non XSAVE systems + * 2) fpu_init_fpstate_user() which is invoked from KVM + */ +void fpstate_init_user(union fpregs_state *state) { - if (!static_cpu_has(X86_FEATURE_FPU)) { + if (!cpu_feature_enabled(X86_FEATURE_FPU)) { fpstate_init_soft(&state->soft); return; } - memset(state, 0, fpu_kernel_xstate_size); + xstate_init_xcomp_bv(&state->xsave, xfeatures_mask_uabi()); - if (static_cpu_has(X86_FEATURE_XSAVES)) - fpstate_init_xstate(&state->xsave); - if (static_cpu_has(X86_FEATURE_FXSR)) + if (cpu_feature_enabled(X86_FEATURE_FXSR)) fpstate_init_fxstate(&state->fxsave); else fpstate_init_fstate(&state->fsave); } -EXPORT_SYMBOL_GPL(fpstate_init); + +#if IS_ENABLED(CONFIG_KVM) +void fpu_init_fpstate_user(struct fpu *fpu) +{ + fpstate_init_user(&fpu->state); +} +EXPORT_SYMBOL_GPL(fpu_init_fpstate_user); +#endif /* Clone current's FPU state on fork */ int fpu_clone(struct task_struct *dst) diff --git a/arch/x86/kernel/fpu/init.c b/arch/x86/kernel/fpu/init.c index 86bc975..37f8726 100644 --- a/arch/x86/kernel/fpu/init.c +++ b/arch/x86/kernel/fpu/init.c @@ -121,10 +121,10 @@ static void __init fpu__init_system_mxcsr(void) static void __init fpu__init_system_generic(void) { /* - * Set up the legacy init FPU context. (xstate init might overwrite this - * with a more modern format, if the CPU supports it.) + * Set up the legacy init FPU context. Will be updated when the + * CPU supports XSAVE[S]. */ - fpstate_init(&init_fpstate); + fpstate_init_user(&init_fpstate); fpu__init_system_mxcsr(); } diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index d6b5f22..259951d 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -15,10 +15,10 @@ #include <asm/fpu/internal.h> #include <asm/fpu/signal.h> #include <asm/fpu/regset.h> -#include <asm/fpu/xstate.h> #include <asm/tlbflush.h> -#include <asm/cpufeature.h> + +#include "xstate.h" /* * Although we spell it out in here, the Processor Trace @@ -389,9 +389,7 @@ static void __init setup_init_fpu_buf(void) setup_xstate_features(); print_xstate_features(); - if (boot_cpu_has(X86_FEATURE_XSAVES)) - init_fpstate.xsave.header.xcomp_bv = XCOMP_BV_COMPACTED_FORMAT | - xfeatures_mask_all; + xstate_init_xcomp_bv(&init_fpstate.xsave, xfeatures_mask_all); /* * Init all the features state with header.xfeatures being 0x0 diff --git a/arch/x86/kernel/fpu/xstate.h b/arch/x86/kernel/fpu/xstate.h new file mode 100644 index 0000000..0789a04 --- /dev/null +++ b/arch/x86/kernel/fpu/xstate.h @@ -0,0 +1,18 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __X86_KERNEL_FPU_XSTATE_H +#define __X86_KERNEL_FPU_XSTATE_H + +#include <asm/cpufeature.h> +#include <asm/fpu/xstate.h> + +static inline void xstate_init_xcomp_bv(struct xregs_state *xsave, u64 mask) +{ + /* + * XRSTORS requires these bits set in xcomp_bv, or it will + * trigger #GP: + */ + if (cpu_feature_enabled(X86_FEATURE_XSAVES)) + xsave->header.xcomp_bv = mask | XCOMP_BV_COMPACTED_FORMAT; +} + +#endif diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index aabd3a2..74712e5 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -10626,14 +10626,6 @@ static int sync_regs(struct kvm_vcpu *vcpu) static void fx_init(struct kvm_vcpu *vcpu) { - if (!vcpu->arch.guest_fpu) - return; - - fpstate_init(&vcpu->arch.guest_fpu->state); - if (boot_cpu_has(X86_FEATURE_XSAVES)) - vcpu->arch.guest_fpu->state.xsave.header.xcomp_bv = - host_xcr0 | XSTATE_COMPACTION_ENABLED; - /* * Ensure guest xcr0 is valid for loading */ @@ -10720,6 +10712,9 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu) pr_err("kvm: failed to allocate vcpu's fpu\n"); goto free_user_fpu; } + + fpu_init_fpstate_user(vcpu->arch.user_fpu); + fpu_init_fpstate_user(vcpu->arch.guest_fpu); fx_init(vcpu); vcpu->arch.maxphyaddr = cpuid_query_maxphyaddr(vcpu);
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