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Subject[PATCH v3 10/22] x86/fpu: Provide fpu_update_guest_xfd() for IA32_XFD emulation
Date
From: Kevin Tian <kevin.tian@intel.com>

Guest XFD can be updated either in the emulation path or in the
restore path.

Provide a wrapper to update guest_fpu::fpstate::xfd. If the guest
fpstate is currently in-use, also update the per-cpu xfd cache and
the actual MSR.

Signed-off-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Jing Liu <jing2.liu@intel.com>
---
arch/x86/include/asm/fpu/api.h | 6 ++++++
arch/x86/kernel/fpu/core.c | 12 ++++++++++++
2 files changed, 18 insertions(+)

diff --git a/arch/x86/include/asm/fpu/api.h b/arch/x86/include/asm/fpu/api.h
index 8e934e571273..100b535cd3de 100644
--- a/arch/x86/include/asm/fpu/api.h
+++ b/arch/x86/include/asm/fpu/api.h
@@ -140,6 +140,12 @@ extern void fpu_free_guest_fpstate(struct fpu_guest *gfpu);
extern int fpu_swap_kvm_fpstate(struct fpu_guest *gfpu, bool enter_guest);
extern int fpu_update_guest_perm_features(struct fpu_guest *guest_fpu);

+#ifdef CONFIG_X86_64
+extern void fpu_update_guest_xfd(struct fpu_guest *guest_fpu, u64 xfd);
+#else
+static inline void fpu_update_guest_xfd(struct fpu_guest *guest_fpu, u64 xfd) { }
+#endif
+
extern void fpu_copy_guest_fpstate_to_uabi(struct fpu_guest *gfpu, void *buf, unsigned int size, u32 pkru);
extern int fpu_copy_uabi_to_guest_fpstate(struct fpu_guest *gfpu, const void *buf, u64 xcr0, u32 *vpkru);

diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
index 2560a95980aa..3daea097c618 100644
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -288,6 +288,18 @@ int fpu_update_guest_perm_features(struct fpu_guest *guest_fpu)
}
EXPORT_SYMBOL_GPL(fpu_update_guest_perm_features);

+#ifdef CONFIG_X86_64
+void fpu_update_guest_xfd(struct fpu_guest *guest_fpu, u64 xfd)
+{
+ fpregs_lock();
+ guest_fpu->fpstate->xfd = xfd;
+ if (guest_fpu->fpstate->in_use)
+ xfd_update_state(guest_fpu->fpstate);
+ fpregs_unlock();
+}
+EXPORT_SYMBOL_GPL(fpu_update_guest_xfd);
+#endif /* CONFIG_X86_64 */
+
int fpu_swap_kvm_fpstate(struct fpu_guest *guest_fpu, bool enter_guest)
{
struct fpstate *guest_fps = guest_fpu->fpstate;
--
2.27.0
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