Currently, fpu->guest_perm is copied from fpu->perm, which is derived from
fpu_kernel_cfg.default_features.
Initialize guest FPU permissions from guest defaults instead of host
defaults. This ensures that any changes to guest_default_{features,size}
are automatically reflected in guest permissions, which in turn guarantees
that fpstate_realloc() allocates a correctly sized XSAVE buffer for guest
FPUs.
Signed-off-by: Chao Gao <chao.gao@xxxxxxxxx>
---
arch/x86/kernel/fpu/core.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
index 0b695c23bbfb..52df97a8a61b 100644
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -542,8 +542,10 @@ void fpstate_reset(struct fpu *fpu)
fpu->perm.__state_perm = fpu_kernel_cfg.default_features;
fpu->perm.__state_size = fpu_kernel_cfg.default_size;
fpu->perm.__user_state_size = fpu_user_cfg.default_size;
- /* Same defaults for guests */
- fpu->guest_perm = fpu->perm;
+
+ fpu->guest_perm.__state_perm = fpu_kernel_cfg.guest_default_features;
+ fpu->guest_perm.__state_size = fpu_kernel_cfg.guest_default_size;
+ fpu->guest_perm.__user_state_size = fpu_user_cfg.guest_default_size;
}
static inline void fpu_inherit_perms(struct fpu *dst_fpu)
--
2.46.1
