[PATCH v5 5/7] x86/fpu: Initialize guest fpstate and FPU pseudo container from guest defaults

[Chao Gao <chao.gao@intel.com>]

fpu_alloc_guest_fpstate() currently uses host defaults to initialize guest
fpstate and pseudo containers. Guest defaults were introduced to
differentiate the features and sizes of host and guest FPUs. Switch to
using guest defaults instead.

Additionally, incorporate the initialization of indicators (is_valloc and
is_guest) into the newly added guest-specific reset function to centralize
the resetting of guest fpstate.

Suggested-by: Chang S. Bae <chang.seok.bae@intel.com>
Signed-off-by: Chao Gao <chao.gao@intel.com>
---
v5: init is_valloc/is_guest in the guest-specific reset function (Chang)
---
 arch/x86/kernel/fpu/core.c | 28 ++++++++++++++++++++--------
 1 file changed, 20 insertions(+), 8 deletions(-)

diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
index e23e435b85c4..f5593f6009a4 100644
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -201,7 +201,20 @@ void fpu_reset_from_exception_fixup(void)
 }
 
 #if IS_ENABLED(CONFIG_KVM)
-static void __fpstate_reset(struct fpstate *fpstate, u64 xfd);
+static void __guest_fpstate_reset(struct fpstate *fpstate, u64 xfd)
+{
+	/* Initialize sizes and feature masks */
+	fpstate->size		= guest_default_cfg.size;
+	fpstate->user_size	= guest_default_cfg.user_size;
+	fpstate->xfeatures	= guest_default_cfg.features;
+	fpstate->user_xfeatures	= guest_default_cfg.user_features;
+	fpstate->xfd		= xfd;
+
+	/* Initialize indicators to reflect properties of the fpstate */
+	fpstate->is_valloc	= true;
+	fpstate->is_guest	= true;
+}
+
 
 static void fpu_lock_guest_permissions(void)
 {
@@ -226,19 +239,18 @@ 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 = guest_default_cfg.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);
+	__guest_fpstate_reset(fpstate, 0);
 	fpstate_init_user(fpstate);
-	fpstate->is_valloc	= true;
-	fpstate->is_guest	= true;
 
 	gfpu->fpstate		= fpstate;
-	gfpu->xfeatures		= fpu_kernel_cfg.default_features;
+	gfpu->xfeatures		= guest_default_cfg.features;
 
 	/*
 	 * KVM sets the FP+SSE bits in the XSAVE header when copying FPU state
@@ -250,8 +262,8 @@ bool fpu_alloc_guest_fpstate(struct fpu_guest *gfpu)
 	 * all features that can expand the uABI size must be opt-in.
 	 */
 	gfpu->uabi_size		= sizeof(struct kvm_xsave);
-	if (WARN_ON_ONCE(fpu_user_cfg.default_size > gfpu->uabi_size))
-		gfpu->uabi_size = fpu_user_cfg.default_size;
+	if (WARN_ON_ONCE(guest_default_cfg.user_size > gfpu->uabi_size))
+		gfpu->uabi_size = guest_default_cfg.user_size;
 
 	fpu_lock_guest_permissions();
 
-- 
2.46.1