[RFC PATCH 08/14] KVM: VMX: Move shared VMX data structures into VAC

Anish Ghulati
2023-11-07T20:21:03Z

Move vmxarea and current_vmcs into VAC.

Move VPID bitmap into the VAC

TODO: Explain why this data needs to be shared among multiple KVM
modules and moved into VAC.

Signed-off-by: Venkatesh Srinivas <venkateshs@chromium.org>
Signed-off-by: Anish Ghulati <aghulati@google.com>
---
arch/x86/kvm/vmx/nested.c | 1 +
arch/x86/kvm/vmx/vac.c | 47 +++++++++++++++++++++++++++++++++++++++
arch/x86/kvm/vmx/vac.h | 12 ++++++++++
arch/x86/kvm/vmx/vmx.c | 41 +++++-----------------------------
arch/x86/kvm/vmx/vmx.h | 2 --
5 files changed, 65 insertions(+), 38 deletions(-)
create mode 100644 arch/x86/kvm/vmx/vac.h

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index c5ec0ef51ff7..5c6ac7662453 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -14,6 +14,7 @@
#include "pmu.h"
#include "sgx.h"
#include "trace.h"
+#include "vac.h"
#include "vmx.h"
#include "x86.h"
#include "smm.h"
diff --git a/arch/x86/kvm/vmx/vac.c b/arch/x86/kvm/vmx/vac.c
index 4aabf16d2fc0..7b8ade0fb97f 100644
--- a/arch/x86/kvm/vmx/vac.c
+++ b/arch/x86/kvm/vmx/vac.c
@@ -1,2 +1,49 @@
// SPDX-License-Identifier: GPL-2.0-only

+#include <asm/percpu.h>
+#include <linux/percpu-defs.h>
+
+#include "vac.h"
+
+
+static DEFINE_PER_CPU(struct vmcs *, vmxarea);
+
+DEFINE_PER_CPU(struct vmcs *, current_vmcs);
+
+void vac_set_vmxarea(struct vmcs *vmcs, int cpu)
+{
+ per_cpu(vmxarea, cpu) = vmcs;
+}
+
+struct vmcs *vac_get_vmxarea(int cpu)
+{
+ return per_cpu(vmxarea, cpu);
+}
+
+static DECLARE_BITMAP(vmx_vpid_bitmap, VMX_NR_VPIDS);
+static DEFINE_SPINLOCK(vmx_vpid_lock);
+
+int allocate_vpid(void)
+{
+ int vpid;
+
+ if (!enable_vpid)
+ return 0;
+ spin_lock(&vmx_vpid_lock);
+ vpid = find_first_zero_bit(vmx_vpid_bitmap, VMX_NR_VPIDS);
+ if (vpid < VMX_NR_VPIDS)
+ __set_bit(vpid, vmx_vpid_bitmap);
+ else
+ vpid = 0;
+ spin_unlock(&vmx_vpid_lock);
+ return vpid;
+}
+
+void free_vpid(int vpid)
+{
+ if (!enable_vpid || vpid == 0)
+ return;
+ spin_lock(&vmx_vpid_lock);
+ __clear_bit(vpid, vmx_vpid_bitmap);
+ spin_unlock(&vmx_vpid_lock);
+}
diff --git a/arch/x86/kvm/vmx/vac.h b/arch/x86/kvm/vmx/vac.h
new file mode 100644
index 000000000000..46c54fe7447d
--- /dev/null
+++ b/arch/x86/kvm/vmx/vac.h
@@ -0,0 +1,12 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <asm/vmx.h>
+
+#include "../vac.h"
+#include "vmcs.h"
+
+void vac_set_vmxarea(struct vmcs *vmcs, int cpu);
+
+struct vmcs *vac_get_vmxarea(int cpu);
+int allocate_vpid(void);
+void free_vpid(int vpid);
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 7fea84a17edf..407e37810419 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -60,6 +60,7 @@
#include "pmu.h"
#include "sgx.h"
#include "trace.h"
+#include "vac.h"
#include "vmcs.h"
#include "vmcs12.h"
#include "vmx.h"
@@ -455,17 +456,12 @@ noinline void invept_error(unsigned long ext, u64 eptp, gpa_t gpa)
ext, eptp, gpa);
}

-static DEFINE_PER_CPU(struct vmcs *, vmxarea);
-DEFINE_PER_CPU(struct vmcs *, current_vmcs);
/*
* We maintain a per-CPU linked-list of VMCS loaded on that CPU. This is needed
* when a CPU is brought down, and we need to VMCLEAR all VMCSs loaded on it.
*/
static DEFINE_PER_CPU(struct list_head, loaded_vmcss_on_cpu);

-static DECLARE_BITMAP(vmx_vpid_bitmap, VMX_NR_VPIDS);
-static DEFINE_SPINLOCK(vmx_vpid_lock);
-
struct vmcs_config vmcs_config __ro_after_init;
struct vmx_capability vmx_capability __ro_after_init;

@@ -2792,7 +2788,7 @@ static int kvm_cpu_vmxon(u64 vmxon_pointer)
static int vmx_hardware_enable(void)
{
int cpu = raw_smp_processor_id();
- u64 phys_addr = __pa(per_cpu(vmxarea, cpu));
+ u64 phys_addr = __pa(vac_get_vmxarea(cpu));
int r;

if (cr4_read_shadow() & X86_CR4_VMXE)
@@ -2921,8 +2917,8 @@ static void free_kvm_area(void)
int cpu;

for_each_possible_cpu(cpu) {
- free_vmcs(per_cpu(vmxarea, cpu));
- per_cpu(vmxarea, cpu) = NULL;
+ free_vmcs(vac_get_vmxarea(cpu));
+ vac_set_vmxarea(NULL, cpu);
}
}

@@ -2952,7 +2948,7 @@ static __init int alloc_kvm_area(void)
if (kvm_is_using_evmcs())
vmcs->hdr.revision_id = vmcs_config.revision_id;

- per_cpu(vmxarea, cpu) = vmcs;
+ vac_set_vmxarea(vmcs, cpu);
}
return 0;
}
@@ -3897,31 +3893,6 @@ static void seg_setup(int seg)
vmcs_write32(sf->ar_bytes, ar);
}

-int allocate_vpid(void)
-{
- int vpid;
-
- if (!enable_vpid)
- return 0;
- spin_lock(&vmx_vpid_lock);
- vpid = find_first_zero_bit(vmx_vpid_bitmap, VMX_NR_VPIDS);
- if (vpid < VMX_NR_VPIDS)
- __set_bit(vpid, vmx_vpid_bitmap);
- else
- vpid = 0;
- spin_unlock(&vmx_vpid_lock);
- return vpid;
-}
-
-void free_vpid(int vpid)
-{
- if (!enable_vpid || vpid == 0)
- return;
- spin_lock(&vmx_vpid_lock);
- __clear_bit(vpid, vmx_vpid_bitmap);
- spin_unlock(&vmx_vpid_lock);
-}
-
static void vmx_msr_bitmap_l01_changed(struct vcpu_vmx *vmx)
{
/*
@@ -8538,8 +8509,6 @@ static __init int hardware_setup(void)
kvm_caps.has_bus_lock_exit = cpu_has_vmx_bus_lock_detection();
kvm_caps.has_notify_vmexit = cpu_has_notify_vmexit();

- set_bit(0, vmx_vpid_bitmap); /* 0 is reserved for host */
-
if (enable_ept)
kvm_mmu_set_ept_masks(enable_ept_ad_bits,
cpu_has_vmx_ept_execute_only());
diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h
index 476119670d82..03b11159fde5 100644
--- a/arch/x86/kvm/vmx/vmx.h
+++ b/arch/x86/kvm/vmx/vmx.h
@@ -376,8 +376,6 @@ struct kvm_vmx {

void vmx_vcpu_load_vmcs(struct kvm_vcpu *vcpu, int cpu,
struct loaded_vmcs *buddy);
-int allocate_vpid(void);
-void free_vpid(int vpid);
void vmx_set_constant_host_state(struct vcpu_vmx *vmx);
void vmx_prepare_switch_to_guest(struct kvm_vcpu *vcpu);
void vmx_set_host_fs_gs(struct vmcs_host_state *host, u16 fs_sel, u16 gs_sel,
--
2.42.0.869.gea05f2083d-goog