linux-kernel - [PATCH v3 07/10] x86/fpu/xstate: Initialize guest fpstate with fpu_guest

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Message-ID: <20250307164123.1613414-8-chao.gao@intel.com>
Date: Sat,  8 Mar 2025 00:41:20 +0800
From: Chao Gao <chao.gao@...el.com>
To: chao.gao@...el.com,
	tglx@...utronix.de,
	dave.hansen@...el.com,
	x86@...nel.org,
	seanjc@...gle.com,
	pbonzini@...hat.com,
	linux-kernel@...r.kernel.org,
	kvm@...r.kernel.org
Cc: peterz@...radead.org,
	rick.p.edgecombe@...el.com,
	weijiang.yang@...el.com,
	john.allen@....com,
	bp@...en8.de,
	Maxim Levitsky <mlevitsk@...hat.com>
Subject: [PATCH v3 07/10] x86/fpu/xstate: Initialize guest fpstate with fpu_guest_config

From: Yang Weijiang <weijiang.yang@...el.com>

Use fpu_guest_cfg to initialize the guest fpstate and the guest FPU pseduo
container.

The user_* fields remain unchanged for compatibility with KVM uAPIs.

Inline the logic of __fpstate_reset() to directly utilize fpu_guest_cfg.

Note fpu_guest_cfg and fpu_kernel_cfg remain the same for now. So there
is no functional change.

Signed-off-by: Yang Weijiang <weijiang.yang@...el.com>
Signed-off-by: Chao Gao <chao.gao@...el.com>
Reviewed-by: Maxim Levitsky <mlevitsk@...hat.com>
Reviewed-by: Rick Edgecombe <rick.p.edgecombe@...el.com>
---
 arch/x86/kernel/fpu/core.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
index d7ae684adbad..9cb800918b6d 100644
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -194,8 +194,6 @@ void fpu_reset_from_exception_fixup(void)
 }
 
 #if IS_ENABLED(CONFIG_KVM)
-static void __fpstate_reset(struct fpstate *fpstate, u64 xfd);
-
 static void fpu_lock_guest_permissions(struct fpu_guest *gfpu)
 {
 	struct fpu_state_perm *fpuperm;
@@ -219,19 +217,22 @@ bool fpu_alloc_guest_fpstate(struct fpu_guest *gfpu)
 	struct fpstate *fpstate;
 	unsigned int size;
 
-	size = fpu_kernel_cfg.default_size + ALIGN(offsetof(struct fpstate, regs), 64);
+	size = fpu_guest_cfg.default_size + ALIGN(offsetof(struct fpstate, regs), 64);
+
 	fpstate = vzalloc(size);
 	if (!fpstate)
 		return false;
 
-	/* Leave xfd to 0 (the reset value defined by spec) */
-	__fpstate_reset(fpstate, 0);
+	fpstate->size		= fpu_guest_cfg.default_size;
+	fpstate->xfeatures	= fpu_guest_cfg.default_features;
+	fpstate->user_size	= fpu_user_cfg.default_size;
+	fpstate->user_xfeatures	= fpu_user_cfg.default_features;
 	fpstate_init_user(fpstate);
 	fpstate->is_valloc	= true;
 	fpstate->is_guest	= true;
 
 	gfpu->fpstate		= fpstate;
-	gfpu->xfeatures		= fpu_kernel_cfg.default_features;
+	gfpu->xfeatures		= fpu_guest_cfg.default_features;
 
 	/*
 	 * KVM sets the FP+SSE bits in the XSAVE header when copying FPU state
-- 
2.46.1