[PATCH v3 3/4] KVM: x86: Move .pmu_ops to kvm_x86_init_ops and tag as __initdata

From: Like Xu
Date: Mon Mar 07 2022 - 06:59:54 EST


From: Like Xu <likexu@xxxxxxxxxxx>

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@xxxxxxxxxx>
Signed-off-by: Like Xu <likexu@xxxxxxxxxxx>
Reviewed-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
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