linux-hardening - [RFC PATCH v2 06/19] KVM: x86: Add kvm_x86_ops.fault

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Date: Sun, 12 Nov 2023 21:23:13 -0500
From: Mickaël Salaün <mic@...ikod.net>
To: Borislav Petkov <bp@...en8.de>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	"H . Peter Anvin" <hpa@...or.com>,
	Ingo Molnar <mingo@...hat.com>,
	Kees Cook <keescook@...omium.org>,
	Paolo Bonzini <pbonzini@...hat.com>,
	Sean Christopherson <seanjc@...gle.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Vitaly Kuznetsov <vkuznets@...hat.com>,
	Wanpeng Li <wanpengli@...cent.com>
Cc: Mickaël Salaün <mic@...ikod.net>,
	Alexander Graf <graf@...zon.com>,
	Chao Peng <chao.p.peng@...ux.intel.com>,
	"Edgecombe, Rick P" <rick.p.edgecombe@...el.com>,
	Forrest Yuan Yu <yuanyu@...gle.com>,
	James Gowans <jgowans@...zon.com>,
	James Morris <jamorris@...ux.microsoft.com>,
	John Andersen <john.s.andersen@...el.com>,
	"Madhavan T . Venkataraman" <madvenka@...ux.microsoft.com>,
	Marian Rotariu <marian.c.rotariu@...il.com>,
	Mihai Donțu <mdontu@...defender.com>,
	Nicușor Cîțu <nicu.citu@...oud.com>,
	Thara Gopinath <tgopinath@...rosoft.com>,
	Trilok Soni <quic_tsoni@...cinc.com>,
	Wei Liu <wei.liu@...nel.org>,
	Will Deacon <will@...nel.org>,
	Yu Zhang <yu.c.zhang@...ux.intel.com>,
	Zahra Tarkhani <ztarkhani@...rosoft.com>,
	Ștefan Șicleru <ssicleru@...defender.com>,
	dev@...ts.cloudhypervisor.org,
	kvm@...r.kernel.org,
	linux-hardening@...r.kernel.org,
	linux-hyperv@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	linux-security-module@...r.kernel.org,
	qemu-devel@...gnu.org,
	virtualization@...ts.linux-foundation.org,
	x86@...nel.org,
	xen-devel@...ts.xenproject.org
Subject: [RFC PATCH v2 06/19] KVM: x86: Add kvm_x86_ops.fault_gva()

This function is needed for kvm_mmu_page_fault() to create synthetic
page faults.

Code originally written by Mihai Donțu and Nicușor Cîțu:
https://lore.kernel.org/r/20211006173113.26445-18-alazar@bitdefender.com
Renamed fault_gla() to fault_gva() and use the new
EPT_VIOLATION_GVA_IS_VALID.

Cc: Borislav Petkov <bp@...en8.de>
Cc: Dave Hansen <dave.hansen@...ux.intel.com>
Cc: H. Peter Anvin <hpa@...or.com>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: Kees Cook <keescook@...omium.org>
Cc: Madhavan T. Venkataraman <madvenka@...ux.microsoft.com>
Cc: Paolo Bonzini <pbonzini@...hat.com>
Cc: Sean Christopherson <seanjc@...gle.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Vitaly Kuznetsov <vkuznets@...hat.com>
Cc: Wanpeng Li <wanpengli@...cent.com>
Co-developed-by: Mihai Donțu <mdontu@...defender.com>
Signed-off-by: Mihai Donțu <mdontu@...defender.com>
Co-developed-by: Nicușor Cîțu <nicu.citu@...oud.com>
Signed-off-by: Nicușor Cîțu <nicu.citu@...oud.com>
Signed-off-by: Mickaël Salaün <mic@...ikod.net>
---
 arch/x86/include/asm/kvm-x86-ops.h |  1 +
 arch/x86/include/asm/kvm_host.h    |  2 ++
 arch/x86/kvm/svm/svm.c             |  9 +++++++++
 arch/x86/kvm/vmx/vmx.c             | 10 ++++++++++
 4 files changed, 22 insertions(+)

diff --git a/arch/x86/include/asm/kvm-x86-ops.h b/arch/x86/include/asm/kvm-x86-ops.h
index e3054e3e46d5..ba3db679db2b 100644
--- a/arch/x86/include/asm/kvm-x86-ops.h
+++ b/arch/x86/include/asm/kvm-x86-ops.h
@@ -134,6 +134,7 @@ KVM_X86_OP(msr_filter_changed)
 KVM_X86_OP(complete_emulated_msr)
 KVM_X86_OP(vcpu_deliver_sipi_vector)
 KVM_X86_OP_OPTIONAL_RET0(vcpu_get_apicv_inhibit_reasons);
+KVM_X86_OP(fault_gva)
 
 #undef KVM_X86_OP
 #undef KVM_X86_OP_OPTIONAL
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index dff10051e9b6..0415dacd4b28 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1750,6 +1750,8 @@ struct kvm_x86_ops {
 	 * Returns vCPU specific APICv inhibit reasons
 	 */
 	unsigned long (*vcpu_get_apicv_inhibit_reasons)(struct kvm_vcpu *vcpu);
+
+	u64 (*fault_gva)(struct kvm_vcpu *vcpu);
 };
 
 struct kvm_x86_nested_ops {
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index beea99c8e8e0..d32517a2cf9c 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -4906,6 +4906,13 @@ static int svm_vm_init(struct kvm *kvm)
 	return 0;
 }
 
+static u64 svm_fault_gva(struct kvm_vcpu *vcpu)
+{
+	const struct vcpu_svm *svm = to_svm(vcpu);
+
+	return svm->vcpu.arch.cr2 ? svm->vcpu.arch.cr2 : ~0ull;
+}
+
 static struct kvm_x86_ops svm_x86_ops __initdata = {
 	.name = KBUILD_MODNAME,
 
@@ -5037,6 +5044,8 @@ static struct kvm_x86_ops svm_x86_ops __initdata = {
 
 	.vcpu_deliver_sipi_vector = svm_vcpu_deliver_sipi_vector,
 	.vcpu_get_apicv_inhibit_reasons = avic_vcpu_get_apicv_inhibit_reasons,
+
+	.fault_gva = svm_fault_gva,
 };
 
 /*
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 1b1581f578b0..a8158bc1dda9 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -8233,6 +8233,14 @@ static void vmx_vm_destroy(struct kvm *kvm)
 	free_pages((unsigned long)kvm_vmx->pid_table, vmx_get_pid_table_order(kvm));
 }
 
+static u64 vmx_fault_gva(struct kvm_vcpu *vcpu)
+{
+	if (vcpu->arch.exit_qualification & EPT_VIOLATION_GVA_IS_VALID)
+		return vmcs_readl(GUEST_LINEAR_ADDRESS);
+
+	return ~0ull;
+}
+
 static struct kvm_x86_ops vmx_x86_ops __initdata = {
 	.name = KBUILD_MODNAME,
 
@@ -8373,6 +8381,8 @@ static struct kvm_x86_ops vmx_x86_ops __initdata = {
 	.complete_emulated_msr = kvm_complete_insn_gp,
 
 	.vcpu_deliver_sipi_vector = kvm_vcpu_deliver_sipi_vector,
+
+	.fault_gva = vmx_fault_gva,
 };
 
 static unsigned int vmx_handle_intel_pt_intr(void)
-- 
2.42.1