linux-kernel - [PATCH v3 3/4] KVM: x86: Move .pmu_ops to kvm_x86_init_ops and tag as _

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Date:   Mon,  7 Mar 2022 19:59:19 +0800
From:   Like Xu <like.xu.linux@...il.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     Sean Christopherson <seanjc@...gle.com>, kvm@...r.kernel.org,
        Jim Mattson <jmattson@...gle.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Joerg Roedel <joro@...tes.org>, linux-kernel@...r.kernel.org
Subject: [PATCH v3 3/4] KVM: x86: Move .pmu_ops to kvm_x86_init_ops and tag as __initdata

From: Like Xu <likexu@...cent.com>

The pmu_ops should be moved to kvm_x86_init_ops and tagged as __initdata.
That'll save those precious few bytes, and more importantly make
the original ops unreachable, i.e. make it harder to sneak in post-init
modification bugs.

Suggested-by: Sean Christopherson <seanjc@...gle.com>
Signed-off-by: Like Xu <likexu@...cent.com>
Reviewed-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/include/asm/kvm_host.h | 3 +--
 arch/x86/kvm/svm/pmu.c          | 2 +-
 arch/x86/kvm/svm/svm.c          | 2 +-
 arch/x86/kvm/vmx/pmu_intel.c    | 2 +-
 arch/x86/kvm/vmx/vmx.c          | 2 +-
 arch/x86/kvm/x86.c              | 2 +-
 6 files changed, 6 insertions(+), 7 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index fdb62aba73ef..5d7297d1d71b 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1448,8 +1448,6 @@ struct kvm_x86_ops {
 	int cpu_dirty_log_size;
 	void (*update_cpu_dirty_logging)(struct kvm_vcpu *vcpu);
 
-	/* pmu operations of sub-arch */
-	const struct kvm_pmu_ops *pmu_ops;
 	const struct kvm_x86_nested_ops *nested_ops;
 
 	void (*vcpu_blocking)(struct kvm_vcpu *vcpu);
@@ -1520,6 +1518,7 @@ struct kvm_x86_init_ops {
 	unsigned int (*handle_intel_pt_intr)(void);
 
 	struct kvm_x86_ops *runtime_ops;
+	struct kvm_pmu_ops *pmu_ops;
 };
 
 struct kvm_arch_async_pf {
diff --git a/arch/x86/kvm/svm/pmu.c b/arch/x86/kvm/svm/pmu.c
index d4de52409335..d4876e6708c5 100644
--- a/arch/x86/kvm/svm/pmu.c
+++ b/arch/x86/kvm/svm/pmu.c
@@ -320,7 +320,7 @@ static void amd_pmu_reset(struct kvm_vcpu *vcpu)
 	}
 }
 
-struct kvm_pmu_ops amd_pmu_ops = {
+struct kvm_pmu_ops amd_pmu_ops __initdata = {
 	.pmc_perf_hw_id = amd_pmc_perf_hw_id,
 	.pmc_is_enabled = amd_pmc_is_enabled,
 	.pmc_idx_to_pmc = amd_pmc_idx_to_pmc,
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index fc5222a0f506..21d85c8929d5 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -4613,7 +4613,6 @@ static struct kvm_x86_ops svm_x86_ops __initdata = {
 
 	.sched_in = svm_sched_in,
 
-	.pmu_ops = &amd_pmu_ops,
 	.nested_ops = &svm_nested_ops,
 
 	.deliver_interrupt = svm_deliver_interrupt,
@@ -4887,6 +4886,7 @@ static struct kvm_x86_init_ops svm_init_ops __initdata = {
 	.check_processor_compatibility = svm_check_processor_compat,
 
 	.runtime_ops = &svm_x86_ops,
+	.pmu_ops = &amd_pmu_ops,
 };
 
 static int __init svm_init(void)
diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index 4e5b1eeeb77c..2c783ad122b9 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -715,7 +715,7 @@ static void intel_pmu_cleanup(struct kvm_vcpu *vcpu)
 		intel_pmu_release_guest_lbr_event(vcpu);
 }
 
-struct kvm_pmu_ops intel_pmu_ops = {
+struct kvm_pmu_ops intel_pmu_ops __initdata = {
 	.pmc_perf_hw_id = intel_pmc_perf_hw_id,
 	.pmc_is_enabled = intel_pmc_is_enabled,
 	.pmc_idx_to_pmc = intel_pmc_idx_to_pmc,
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index e8963f5af618..06088e26adae 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -7823,7 +7823,6 @@ static struct kvm_x86_ops vmx_x86_ops __initdata = {
 	.cpu_dirty_log_size = PML_ENTITY_NUM,
 	.update_cpu_dirty_logging = vmx_update_cpu_dirty_logging,
 
-	.pmu_ops = &intel_pmu_ops,
 	.nested_ops = &vmx_nested_ops,
 
 	.pi_update_irte = vmx_pi_update_irte,
@@ -8078,6 +8077,7 @@ static struct kvm_x86_init_ops vmx_init_ops __initdata = {
 	.handle_intel_pt_intr = NULL,
 
 	.runtime_ops = &vmx_x86_ops,
+	.pmu_ops = &intel_pmu_ops,
 };
 
 static void vmx_cleanup_l1d_flush(void)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index dcaeedeef675..0a76f7281e74 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -11536,7 +11536,7 @@ int kvm_arch_hardware_setup(void *opaque)
 		return r;
 
 	memcpy(&kvm_x86_ops, ops->runtime_ops, sizeof(kvm_x86_ops));
-	memcpy(&kvm_pmu_ops, kvm_x86_ops.pmu_ops, sizeof(kvm_pmu_ops));
+	memcpy(&kvm_pmu_ops, ops->pmu_ops, sizeof(kvm_pmu_ops));
 	kvm_ops_static_call_update();
 
 	kvm_register_perf_callbacks(ops->handle_intel_pt_intr);
-- 
2.35.1