[PATCH v4 17/21] x86/fpu: Add uabi_size to guest_fpu
From: Yang Zhong <hidden>
Date: 2021-12-29 13:15:18
Also in:
kvm, linux-kselftest, lkml
Subsystem:
the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
From: Thomas Gleixner <redacted> Userspace needs to inquire KVM about the buffer size to work with the new KVM_SET_XSAVE and KVM_GET_XSAVE2. Add the size info to guest_fpu for KVM to access. Signed-off-by: Thomas Gleixner <redacted> Signed-off-by: Wei Wang <redacted> Signed-off-by: Jing Liu <redacted> Signed-off-by: Yang Zhong <redacted> --- arch/x86/include/asm/fpu/types.h | 5 +++++ arch/x86/kernel/fpu/core.c | 1 + arch/x86/kernel/fpu/xstate.c | 1 + 3 files changed, 7 insertions(+)
diff --git a/arch/x86/include/asm/fpu/types.h b/arch/x86/include/asm/fpu/types.h
index 3795d0573773..eb7cd1139d97 100644
--- a/arch/x86/include/asm/fpu/types.h
+++ b/arch/x86/include/asm/fpu/types.h@@ -522,6 +522,11 @@ struct fpu_guest { */ u64 xfd_err; + /* + * @uabi_size: Size required for save/restore + */ + unsigned int uabi_size; + /* * @fpstate: Pointer to the allocated guest fpstate */
diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
index 3daea097c618..89d679cc819b 100644
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c@@ -240,6 +240,7 @@ bool fpu_alloc_guest_fpstate(struct fpu_guest *gfpu) gfpu->fpstate = fpstate; gfpu->xfeatures = fpu_user_cfg.default_features; gfpu->perm = fpu_user_cfg.default_features; + gfpu->uabi_size = fpu_user_cfg.default_size; fpu_init_guest_permissions(gfpu); return true;
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index 0c0b2323cdec..10fe072f1c92 100644
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c@@ -1545,6 +1545,7 @@ static int fpstate_realloc(u64 xfeatures, unsigned int ksize, newfps->is_confidential = curfps->is_confidential; newfps->in_use = curfps->in_use; guest_fpu->xfeatures |= xfeatures; + guest_fpu->uabi_size = usize; } fpregs_lock();