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Peter Anvin" , Mitchell Levy , Samuel Holland , Kees Cook , Oleg Nesterov , Eric Biggers Subject: [PATCH v6 2/7] x86/fpu: Drop @perm from guest pseudo FPU container Date: Tue, 6 May 2025 17:36:07 +0800 Message-ID: <20250506093740.2864458-3-chao.gao@intel.com> X-Mailer: git-send-email 2.46.1 In-Reply-To: <20250506093740.2864458-1-chao.gao@intel.com> References: <20250506093740.2864458-1-chao.gao@intel.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Remove @perm from the guest pseudo FPU container. The field is initialized during allocation and never used later. Rename fpu_init_guest_permissions() to show that its sole purpose is to lock down guest permissions. Suggested-by: Maxim Levitsky Signed-off-by: Chao Gao Reviewed-by: Chang S. Bae Link: https://lore.kernel.org/kvm/af972fe5981b9e7101b64de43c7be0a8cc165323.= camel@redhat.com/ --- v6: add Chang's Reviewed-by v5: drop the useless fpu_guest argument (Chang) --- arch/x86/include/asm/fpu/types.h | 7 ------- arch/x86/kernel/fpu/core.c | 7 ++----- 2 files changed, 2 insertions(+), 12 deletions(-) diff --git a/arch/x86/include/asm/fpu/types.h b/arch/x86/include/asm/fpu/ty= pes.h index e64db0eb9d27..1c94121acd3d 100644 --- a/arch/x86/include/asm/fpu/types.h +++ b/arch/x86/include/asm/fpu/types.h @@ -535,13 +535,6 @@ struct fpu_guest { */ u64 xfeatures; =20 - /* - * @perm: xfeature bitmap of features which are - * permitted to be enabled for the guest - * vCPU. - */ - u64 perm; - /* * @xfd_err: Save the guest value. */ diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c index 105b1b80d88d..1cda5b78540b 100644 --- a/arch/x86/kernel/fpu/core.c +++ b/arch/x86/kernel/fpu/core.c @@ -212,7 +212,7 @@ void fpu_reset_from_exception_fixup(void) #if IS_ENABLED(CONFIG_KVM) static void __fpstate_reset(struct fpstate *fpstate, u64 xfd); =20 -static void fpu_init_guest_permissions(struct fpu_guest *gfpu) +static void fpu_lock_guest_permissions(void) { struct fpu_state_perm *fpuperm; u64 perm; @@ -228,8 +228,6 @@ static void fpu_init_guest_permissions(struct fpu_guest= *gfpu) WRITE_ONCE(fpuperm->__state_perm, perm | FPU_GUEST_PERM_LOCKED); =20 spin_unlock_irq(¤t->sighand->siglock); - - gfpu->perm =3D perm & ~FPU_GUEST_PERM_LOCKED; } =20 bool fpu_alloc_guest_fpstate(struct fpu_guest *gfpu) @@ -250,7 +248,6 @@ bool fpu_alloc_guest_fpstate(struct fpu_guest *gfpu) =20 gfpu->fpstate =3D fpstate; gfpu->xfeatures =3D fpu_kernel_cfg.default_features; - gfpu->perm =3D fpu_kernel_cfg.default_features; =20 /* * KVM sets the FP+SSE bits in the XSAVE header when copying FPU state @@ -265,7 +262,7 @@ bool fpu_alloc_guest_fpstate(struct fpu_guest *gfpu) if (WARN_ON_ONCE(fpu_user_cfg.default_size > gfpu->uabi_size)) gfpu->uabi_size =3D fpu_user_cfg.default_size; =20 - fpu_init_guest_permissions(gfpu); + fpu_lock_guest_permissions(); =20 return true; } --=20 2.47.1