From 0781d60f658e25fbad3b6e4261f54eb1cd3dc302 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Wed, 5 Jan 2022 04:35:18 -0800 Subject: [PATCH] x86/fpu: Provide fpu_enable_guest_xfd_features() for KVM Provide a wrapper for expanding the guest fpstate buffer according to requested xfeatures. KVM wants to call this wrapper to manage any dynamic xstate used by the guest. Suggested-by: Sean Christopherson Signed-off-by: Sean Christopherson Signed-off-by: Kevin Tian Signed-off-by: Yang Zhong Reviewed-by: Paolo Bonzini Message-Id: <20220105123532.12586-8-yang.zhong@intel.com> [Remove unnecessary 32-bit check. - Paolo] Signed-off-by: Paolo Bonzini --- arch/x86/include/asm/fpu/api.h | 1 + arch/x86/kernel/fpu/core.c | 22 ++++++++++++++++++++++ 2 files changed, 23 insertions(+) diff --git a/arch/x86/include/asm/fpu/api.h b/arch/x86/include/asm/fpu/api.h index d8c2222..1ed2a24 100644 --- a/arch/x86/include/asm/fpu/api.h +++ b/arch/x86/include/asm/fpu/api.h @@ -138,6 +138,7 @@ extern inline u64 xstate_get_guest_group_perm(void); extern bool fpu_alloc_guest_fpstate(struct fpu_guest *gfpu); extern void fpu_free_guest_fpstate(struct fpu_guest *gfpu); extern int fpu_swap_kvm_fpstate(struct fpu_guest *gfpu, bool enter_guest); +extern int fpu_enable_guest_xfd_features(struct fpu_guest *guest_fpu, u64 xfeatures); extern void fpu_copy_guest_fpstate_to_uabi(struct fpu_guest *gfpu, void *buf, unsigned int size, u32 pkru); extern int fpu_copy_uabi_to_guest_fpstate(struct fpu_guest *gfpu, const void *buf, u64 xcr0, u32 *vpkru); diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c index a78bc54..64b2ee3 100644 --- a/arch/x86/kernel/fpu/core.c +++ b/arch/x86/kernel/fpu/core.c @@ -261,6 +261,28 @@ void fpu_free_guest_fpstate(struct fpu_guest *gfpu) } EXPORT_SYMBOL_GPL(fpu_free_guest_fpstate); +/* + * fpu_enable_guest_xfd_features - Check xfeatures against guest perm and enable + * @guest_fpu: Pointer to the guest FPU container + * @xfeatures: Features requested by guest CPUID + * + * Enable all dynamic xfeatures according to guest perm and requested CPUID. + * + * Return: 0 on success, error code otherwise + */ +int fpu_enable_guest_xfd_features(struct fpu_guest *guest_fpu, u64 xfeatures) +{ + lockdep_assert_preemption_enabled(); + + /* Nothing to do if all requested features are already enabled. */ + xfeatures &= ~guest_fpu->xfeatures; + if (!xfeatures) + return 0; + + return __xfd_enable_feature(xfeatures, guest_fpu); +} +EXPORT_SYMBOL_GPL(fpu_enable_guest_xfd_features); + int fpu_swap_kvm_fpstate(struct fpu_guest *guest_fpu, bool enter_guest) { struct fpstate *guest_fps = guest_fpu->fpstate; -- 2.7.4