From: Thomas Gleixner <tglx@linutronix.de>
To: LKML <linux-kernel@vger.kernel.org>
Cc: Jing Liu <jing2.liu@linux.intel.com>,
Yang Zhong <yang.zhong@intel.com>,
Paolo Bonzini <pbonzini@redhat.com>,
x86@kernel.org, kvm@vger.kernel.org,
Sean Christoperson <seanjc@google.com>,
Jin Nakajima <jun.nakajima@intel.com>,
Kevin Tian <kevin.tian@intel.com>
Subject: [patch 2/6] x86/fpu: Prepare guest FPU for dynamically enabled FPU features
Date: Tue, 14 Dec 2021 03:50:22 +0100 (CET) [thread overview]
Message-ID: <20211214024947.878061856@linutronix.de> (raw)
In-Reply-To: 20211214022825.563892248@linutronix.de
To support dynamically enabled FPU features for guests prepare the guest
pseudo FPU container to keep track of the currently enabled xfeatures and
the guest permissions.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
arch/x86/include/asm/fpu/types.h | 13 +++++++++++++
arch/x86/kernel/fpu/core.c | 26 +++++++++++++++++++++++++-
2 files changed, 38 insertions(+), 1 deletion(-)
--- a/arch/x86/include/asm/fpu/types.h
+++ b/arch/x86/include/asm/fpu/types.h
@@ -505,6 +505,19 @@ struct fpu {
*/
struct fpu_guest {
/*
+ * @xfeatures: xfeature bitmap of features which are
+ * currently enabled for the guest vCPU.
+ */
+ u64 xfeatures;
+
+ /*
+ * @perm: xfeature bitmap of features which are
+ * permitted to be enabled for the guest
+ * vCPU.
+ */
+ u64 perm;
+
+ /*
* @fpstate: Pointer to the allocated guest fpstate
*/
struct fpstate *fpstate;
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -201,6 +201,26 @@ void fpu_reset_from_exception_fixup(void
#if IS_ENABLED(CONFIG_KVM)
static void __fpstate_reset(struct fpstate *fpstate);
+static void fpu_init_guest_permissions(struct fpu_guest *gfpu)
+{
+ struct fpu_state_perm *fpuperm;
+ u64 perm;
+
+ if (!IS_ENABLED(CONFIG_X86_64))
+ return;
+
+ spin_lock_irq(¤t->sighand->siglock);
+ fpuperm = ¤t->group_leader->thread.fpu.guest_perm;
+ perm = fpuperm->__state_perm;
+
+ /* First fpstate allocation locks down permissions. */
+ WRITE_ONCE(fpuperm->__state_perm, perm | FPU_GUEST_PERM_LOCKED);
+
+ spin_unlock_irq(¤t->sighand->siglock);
+
+ gfpu->perm = perm & ~FPU_GUEST_PERM_LOCKED;
+}
+
bool fpu_alloc_guest_fpstate(struct fpu_guest *gfpu)
{
struct fpstate *fpstate;
@@ -216,7 +236,11 @@ bool fpu_alloc_guest_fpstate(struct fpu_
fpstate->is_valloc = true;
fpstate->is_guest = true;
- gfpu->fpstate = fpstate;
+ gfpu->fpstate = fpstate;
+ gfpu->xfeatures = fpu_user_cfg.default_features;
+ gfpu->perm = fpu_user_cfg.default_features;
+ fpu_init_guest_permissions(gfpu);
+
return true;
}
EXPORT_SYMBOL_GPL(fpu_alloc_guest_fpstate);
next prev parent reply other threads:[~2021-12-14 2:50 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-14 2:50 [patch 0/6] x86/fpu: Preparatory changes for guest AMX support Thomas Gleixner
2021-12-14 2:50 ` [patch 1/6] x86/fpu: Extend fpu_xstate_prctl() with guest permissions Thomas Gleixner
2021-12-14 5:13 ` Tian, Kevin
2021-12-14 10:37 ` Paolo Bonzini
2021-12-14 2:50 ` Thomas Gleixner [this message]
2021-12-14 2:50 ` [patch 3/6] x86/fpu: Make XFD initialization in __fpstate_reset() a function argument Thomas Gleixner
2021-12-14 2:50 ` [patch 4/6] x86/fpu: Add guest support to xfd_enable_feature() Thomas Gleixner
2021-12-14 6:05 ` Tian, Kevin
2021-12-14 10:21 ` Paolo Bonzini
2021-12-14 13:15 ` Thomas Gleixner
2021-12-15 5:46 ` Tian, Kevin
2021-12-15 9:53 ` Thomas Gleixner
2021-12-15 10:02 ` Tian, Kevin
2021-12-14 2:50 ` [patch 5/6] x86/fpu: Provide fpu_update_guest_xcr0/xfd() Thomas Gleixner
2021-12-14 6:25 ` Tian, Kevin
2021-12-14 15:09 ` Wang, Wei W
2021-12-14 15:40 ` Thomas Gleixner
2021-12-14 16:11 ` Wang, Wei W
2021-12-14 18:04 ` Thomas Gleixner
2021-12-14 19:07 ` Juan Quintela
2021-12-14 20:28 ` Thomas Gleixner
2021-12-14 21:35 ` Juan Quintela
2021-12-15 2:17 ` Wang, Wei W
2021-12-15 10:09 ` Thomas Gleixner
2021-12-15 10:27 ` Paolo Bonzini
2021-12-15 10:41 ` Paolo Bonzini
2021-12-16 1:00 ` Tian, Kevin
2021-12-16 5:36 ` Tian, Kevin
2021-12-16 21:07 ` Paolo Bonzini
2021-12-16 10:21 ` Tian, Kevin
2021-12-16 10:24 ` Paolo Bonzini
2021-12-16 10:26 ` Paolo Bonzini
2021-12-16 13:00 ` Tian, Kevin
2021-12-16 1:04 ` Tian, Kevin
2021-12-16 9:34 ` Thomas Gleixner
2021-12-16 9:59 ` Tian, Kevin
2021-12-16 14:12 ` Thomas Gleixner
2021-12-17 15:33 ` Tian, Kevin
2021-12-15 6:14 ` Tian, Kevin
2021-12-14 2:50 ` [patch 6/6] x86/fpu: Provide kvm_sync_guest_vmexit_xfd_state() Thomas Gleixner
2021-12-15 6:35 ` Liu, Jing2
2021-12-15 9:49 ` Thomas Gleixner
2021-12-14 6:50 ` [patch 0/6] x86/fpu: Preparatory changes for guest AMX support Tian, Kevin
2021-12-14 6:52 ` Liu, Jing2
2021-12-14 7:54 ` Tian, Kevin
2021-12-14 10:42 ` Paolo Bonzini
2021-12-14 13:24 ` Thomas Gleixner
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