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From: Yang Zhong <yang.zhong@intel.com>
To: x86@kernel.org, kvm@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org,
	linux-kselftest@vger.kernel.org, tglx@linutronix.de,
	mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com,
	pbonzini@redhat.com, corbet@lwn.net, shuah@kernel.org
Cc: seanjc@google.com, jun.nakajima@intel.com, kevin.tian@intel.com,
	jing2.liu@linux.intel.com, jing2.liu@intel.com,
	guang.zeng@intel.com, wei.w.wang@intel.com, yang.zhong@intel.com
Subject: [PATCH v4 05/21] x86/fpu: Make XFD initialization in __fpstate_reset() a function argument
Date: Wed, 29 Dec 2021 05:13:12 -0800	[thread overview]
Message-ID: <20211229131328.12283-6-yang.zhong@intel.com> (raw)
In-Reply-To: <20211229131328.12283-1-yang.zhong@intel.com>

From: Jing Liu <jing2.liu@intel.com>

vCPU threads are different from native tasks regarding to the initial XFD
value. While all native tasks follow a fixed value (init_fpstate::xfd)
established by the FPU core at boot, vCPU threads need to obey the reset
value (i.e. ZERO) defined by the specification, to meet the expectation of
the guest.

Let the caller supply an argument and adjust the host and guest related
invocations accordingly.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Jing Liu <jing2.liu@intel.com>
Signed-off-by: Yang Zhong <yang.zhong@intel.com>
---
 arch/x86/kernel/fpu/core.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
index eddeeb4ed2f5..a78bc547fc03 100644
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -199,7 +199,7 @@ void fpu_reset_from_exception_fixup(void)
 }
 
 #if IS_ENABLED(CONFIG_KVM)
-static void __fpstate_reset(struct fpstate *fpstate);
+static void __fpstate_reset(struct fpstate *fpstate, u64 xfd);
 
 static void fpu_init_guest_permissions(struct fpu_guest *gfpu)
 {
@@ -231,7 +231,8 @@ bool fpu_alloc_guest_fpstate(struct fpu_guest *gfpu)
 	if (!fpstate)
 		return false;
 
-	__fpstate_reset(fpstate);
+	/* Leave xfd to 0 (the reset value defined by spec) */
+	__fpstate_reset(fpstate, 0);
 	fpstate_init_user(fpstate);
 	fpstate->is_valloc	= true;
 	fpstate->is_guest	= true;
@@ -454,21 +455,21 @@ void fpstate_init_user(struct fpstate *fpstate)
 		fpstate_init_fstate(fpstate);
 }
 
-static void __fpstate_reset(struct fpstate *fpstate)
+static void __fpstate_reset(struct fpstate *fpstate, u64 xfd)
 {
 	/* Initialize sizes and feature masks */
 	fpstate->size		= fpu_kernel_cfg.default_size;
 	fpstate->user_size	= fpu_user_cfg.default_size;
 	fpstate->xfeatures	= fpu_kernel_cfg.default_features;
 	fpstate->user_xfeatures	= fpu_user_cfg.default_features;
-	fpstate->xfd		= init_fpstate.xfd;
+	fpstate->xfd		= xfd;
 }
 
 void fpstate_reset(struct fpu *fpu)
 {
 	/* Set the fpstate pointer to the default fpstate */
 	fpu->fpstate = &fpu->__fpstate;
-	__fpstate_reset(fpu->fpstate);
+	__fpstate_reset(fpu->fpstate, init_fpstate.xfd);
 
 	/* Initialize the permission related info in fpu */
 	fpu->perm.__state_perm		= fpu_kernel_cfg.default_features;

  parent reply	other threads:[~2021-12-29 13:13 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-12-29 13:13 [PATCH v4 00/21] AMX Support in KVM Yang Zhong
2021-12-29 13:13 ` [PATCH v4 01/21] x86/fpu: Extend fpu_xstate_prctl() with guest permissions Yang Zhong
2021-12-29 13:13 ` [PATCH v4 02/21] x86/fpu: Prepare guest FPU for dynamically enabled FPU features Yang Zhong
2021-12-29 13:13 ` [PATCH v4 03/21] kvm: x86: Fix xstate_required_size() to follow XSTATE alignment rule Yang Zhong
2022-01-04 19:54   ` Sean Christopherson
2021-12-29 13:13 ` [PATCH v4 04/21] kvm: x86: Exclude unpermitted xfeatures at KVM_GET_SUPPORTED_CPUID Yang Zhong
2021-12-29 13:13 ` Yang Zhong [this message]
2021-12-29 13:13 ` [PATCH v4 06/21] x86/fpu: Add guest support to xfd_enable_feature() Yang Zhong
2021-12-29 13:13 ` [PATCH v4 07/21] x86/fpu: Provide fpu_update_guest_perm_features() for guest Yang Zhong
2021-12-29 13:13 ` [PATCH v4 08/21] kvm: x86: Check and enable permitted dynamic xfeatures at KVM_SET_CPUID2 Yang Zhong
2021-12-29 16:55   ` Sean Christopherson
2021-12-30  2:28     ` Tian, Kevin
2021-12-29 13:13 ` [PATCH v4 09/21] x86/fpu: Provide fpu_update_guest_xfd() for IA32_XFD emulation Yang Zhong
2021-12-29 13:13 ` [PATCH v4 10/21] kvm: x86: Add emulation for IA32_XFD Yang Zhong
2022-01-04 19:32   ` Sean Christopherson
2022-01-05  0:22     ` Tian, Kevin
2021-12-29 13:13 ` [PATCH v4 11/21] x86/fpu: Prepare xfd_err in struct fpu_guest Yang Zhong
2021-12-29 13:13 ` [PATCH v4 12/21] kvm: x86: Intercept #NM for saving IA32_XFD_ERR Yang Zhong
2022-01-04 20:01   ` Sean Christopherson
2022-01-05  0:27     ` Tian, Kevin
2021-12-29 13:13 ` [PATCH v4 13/21] kvm: x86: Emulate IA32_XFD_ERR for guest Yang Zhong
2021-12-29 13:13 ` [PATCH v4 14/21] kvm: x86: Disable RDMSR interception of IA32_XFD_ERR Yang Zhong
2022-01-04 19:34   ` Sean Christopherson
2022-01-05  0:23     ` Tian, Kevin
2021-12-29 13:13 ` [PATCH v4 15/21] kvm: x86: Add XCR0 support for Intel AMX Yang Zhong
2021-12-29 13:13 ` [PATCH v4 16/21] kvm: x86: Add CPUID " Yang Zhong
2021-12-29 13:13 ` [PATCH v4 17/21] x86/fpu: Add uabi_size to guest_fpu Yang Zhong
2021-12-29 13:13 ` [PATCH v4 18/21] kvm: x86: Add support for getting/setting expanded xstate buffer Yang Zhong
2022-01-04 19:46   ` Sean Christopherson
2022-01-04 20:45     ` Paolo Bonzini
2022-01-05  4:03       ` Tian, Kevin
2021-12-29 13:13 ` [PATCH v4 19/21] kvm: selftests: Add support for KVM_CAP_XSAVE2 Yang Zhong
2021-12-29 13:13 ` [PATCH v4 20/21] x86/fpu: Provide fpu_sync_guest_vmexit_xfd_state() Yang Zhong
2021-12-29 13:13 ` [PATCH v4 21/21] kvm: x86: Disable interception for IA32_XFD on demand Yang Zhong
2021-12-30  8:46 ` [PATCH v4 00/21] AMX Support in KVM Tian, Kevin
2022-01-04 18:36 ` Paolo Bonzini
2022-01-04 18:54   ` Sean Christopherson
2022-01-05  0:10     ` Tian, Kevin

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