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Subject[PATCH v10 05/10] x86: spp: Introduce user-space SPP IOCTLs
Date
User application, e.g., QEMU or VMI, must initialize SPP
before gets/sets SPP subpages, the dynamic initialization is to
reduce the extra storage cost if the SPP feature is not not used.

Co-developed-by: He Chen <he.chen@linux.intel.com>
Signed-off-by: He Chen <he.chen@linux.intel.com>
Co-developed-by: Zhang Yi <yi.z.zhang@linux.intel.com>
Signed-off-by: Zhang Yi <yi.z.zhang@linux.intel.com>
Signed-off-by: Yang Weijiang <weijiang.yang@intel.com>
---
arch/x86/include/asm/kvm_host.h | 4 ++
arch/x86/kvm/mmu/spp.c | 44 +++++++++++++++
arch/x86/kvm/mmu/spp.h | 9 ++++
arch/x86/kvm/vmx/vmx.c | 15 ++++++
arch/x86/kvm/x86.c | 95 ++++++++++++++++++++++++++++++++-
include/uapi/linux/kvm.h | 3 ++
6 files changed, 169 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index f5145b86d620..c7a9f03f39a7 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1238,6 +1238,10 @@ struct kvm_x86_ops {

bool (*apic_init_signal_blocked)(struct kvm_vcpu *vcpu);
int (*enable_direct_tlbflush)(struct kvm_vcpu *vcpu);
+
+ int (*init_spp)(struct kvm *kvm);
+ int (*flush_subpages)(struct kvm *kvm, u64 gfn, u32 npages);
+ int (*get_inst_len)(struct kvm_vcpu *vcpu);
};

struct kvm_arch_async_pf {
diff --git a/arch/x86/kvm/mmu/spp.c b/arch/x86/kvm/mmu/spp.c
index edf013102137..46a17c3c2cf3 100644
--- a/arch/x86/kvm/mmu/spp.c
+++ b/arch/x86/kvm/mmu/spp.c
@@ -558,3 +558,47 @@ inline u64 construct_spptp(unsigned long root_hpa)
}
EXPORT_SYMBOL_GPL(construct_spptp);

+int kvm_vm_ioctl_get_subpages(struct kvm *kvm,
+ u64 gfn,
+ u32 npages,
+ u32 *access_map)
+{
+ int ret;
+
+ mutex_lock(&kvm->slots_lock);
+ ret = kvm_spp_get_permission(kvm, gfn, npages, access_map);
+ mutex_unlock(&kvm->slots_lock);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(kvm_vm_ioctl_get_subpages);
+
+int kvm_vm_ioctl_set_subpages(struct kvm *kvm,
+ u64 gfn,
+ u32 npages,
+ u32 *access_map)
+{
+ int ret;
+
+ if (!kvm_x86_ops->flush_subpages)
+ return -EINVAL;
+
+ spin_lock(&kvm->mmu_lock);
+ ret = kvm_x86_ops->flush_subpages(kvm, gfn, npages);
+ spin_unlock(&kvm->mmu_lock);
+
+ if (ret < 0)
+ return ret;
+
+ mutex_lock(&kvm->slots_lock);
+ spin_lock(&kvm->mmu_lock);
+
+ ret = kvm_spp_set_permission(kvm, gfn, npages, access_map);
+
+ spin_unlock(&kvm->mmu_lock);
+ mutex_unlock(&kvm->slots_lock);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(kvm_vm_ioctl_set_subpages);
+
diff --git a/arch/x86/kvm/mmu/spp.h b/arch/x86/kvm/mmu/spp.h
index a636d09f6db0..370a6b71e143 100644
--- a/arch/x86/kvm/mmu/spp.h
+++ b/arch/x86/kvm/mmu/spp.h
@@ -3,6 +3,7 @@
#define __KVM_X86_VMX_SPP_H

#define FULL_SPP_ACCESS ((u32)((1ULL << 32) - 1))
+#define KVM_SUBPAGE_MAX_PAGES 512

int kvm_spp_get_permission(struct kvm *kvm, u64 gfn, u32 npages,
u32 *access_map);
@@ -11,6 +12,14 @@ int kvm_spp_set_permission(struct kvm *kvm, u64 gfn, u32 npages,
int kvm_spp_mark_protection(struct kvm *kvm, u64 gfn, u32 access);
bool is_spp_spte(struct kvm_mmu_page *sp);
inline u64 construct_spptp(unsigned long root_hpa);
+int kvm_vm_ioctl_get_subpages(struct kvm *kvm,
+ u64 gfn,
+ u32 npages,
+ u32 *access_map);
+int kvm_vm_ioctl_set_subpages(struct kvm *kvm,
+ u64 gfn,
+ u32 npages,
+ u32 *access_map);
int kvm_spp_setup_structure(struct kvm_vcpu *vcpu,
u32 access_map, gfn_t gfn);
int vmx_spp_flush_sppt(struct kvm *kvm, u64 gfn_base, u32 npages);
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 5713e8a6224c..24e4e1c47f42 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -1424,6 +1424,11 @@ static bool emulation_required(struct kvm_vcpu *vcpu)
return emulate_invalid_guest_state && !guest_state_valid(vcpu);
}

+static int vmx_get_inst_len(struct kvm_vcpu *vcpu)
+{
+ return vmcs_read32(VM_EXIT_INSTRUCTION_LEN);
+}
+
static void vmx_decache_cr0_guest_bits(struct kvm_vcpu *vcpu);

unsigned long vmx_get_rflags(struct kvm_vcpu *vcpu)
@@ -7705,6 +7710,12 @@ static __init int hardware_setup(void)
kvm_x86_ops->enable_log_dirty_pt_masked = NULL;
}

+ if (!spp_supported) {
+ kvm_x86_ops->flush_subpages = NULL;
+ kvm_x86_ops->init_spp = NULL;
+ kvm_x86_ops->get_inst_len = NULL;
+ }
+
if (!cpu_has_vmx_preemption_timer())
enable_preemption_timer = false;

@@ -7917,6 +7928,10 @@ static struct kvm_x86_ops vmx_x86_ops __ro_after_init = {
.nested_get_evmcs_version = NULL,
.need_emulation_on_page_fault = vmx_need_emulation_on_page_fault,
.apic_init_signal_blocked = vmx_apic_init_signal_blocked,
+
+ .flush_subpages = vmx_spp_flush_sppt,
+ .init_spp = vmx_spp_init,
+ .get_inst_len = vmx_get_inst_len,
};

static void vmx_cleanup_l1d_flush(void)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index cf917139de6b..4565181fd0c5 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -26,6 +26,7 @@
#include "cpuid.h"
#include "pmu.h"
#include "hyperv.h"
+#include "mmu/spp.h"

#include <linux/clocksource.h>
#include <linux/interrupt.h>
@@ -3335,6 +3336,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
case KVM_CAP_HYPERV_ENLIGHTENED_VMCS:
r = kvm_x86_ops->nested_enable_evmcs != NULL;
break;
+ case KVM_CAP_X86_SPP:
+ r = KVM_SUBPAGE_MAX_PAGES;
+ break;
default:
break;
}
@@ -4114,7 +4118,6 @@ static int kvm_vcpu_ioctl_enable_cap(struct kvm_vcpu *vcpu,
return -ENOTTY;

return kvm_x86_ops->enable_direct_tlbflush(vcpu);
-
default:
return -EINVAL;
}
@@ -4830,6 +4833,9 @@ int kvm_vm_ioctl_enable_cap(struct kvm *kvm,
kvm->arch.exception_payload_enabled = cap->args[0];
r = 0;
break;
+ case KVM_CAP_X86_SPP:
+ r = kvm_x86_ops->init_spp(kvm);
+ break;
default:
r = -EINVAL;
break;
@@ -5134,6 +5140,93 @@ long kvm_arch_vm_ioctl(struct file *filp,
case KVM_SET_PMU_EVENT_FILTER:
r = kvm_vm_ioctl_set_pmu_event_filter(kvm, argp);
break;
+ case KVM_SUBPAGES_GET_ACCESS: {
+ struct kvm_subpage spp_info, *pinfo;
+ u32 total;
+
+ r = -ENODEV;
+ if (!kvm->arch.spp_active)
+ goto out;
+
+ r = -EFAULT;
+ if (copy_from_user(&spp_info, argp, sizeof(spp_info)))
+ goto out;
+
+ r = -EINVAL;
+ if (spp_info.flags != 0 ||
+ spp_info.npages > KVM_SUBPAGE_MAX_PAGES)
+ goto out;
+ r = 0;
+ if (!spp_info.npages)
+ goto out;
+
+ total = sizeof(spp_info) +
+ sizeof(spp_info.access_map[0]) * spp_info.npages;
+ pinfo = kvzalloc(total, GFP_KERNEL_ACCOUNT);
+
+ r = -ENOMEM;
+ if (!pinfo)
+ goto out;
+
+ r = -EFAULT;
+ if (copy_from_user(pinfo, argp, total))
+ goto out;
+
+ r = kvm_vm_ioctl_get_subpages(kvm,
+ pinfo->gfn_base,
+ pinfo->npages,
+ pinfo->access_map);
+ if (r != pinfo->npages)
+ goto out;
+
+ r = -EFAULT;
+ if (copy_to_user(argp, pinfo, total))
+ goto out;
+
+ kfree(pinfo);
+ r = pinfo->npages;
+ break;
+ }
+ case KVM_SUBPAGES_SET_ACCESS: {
+ struct kvm_subpage spp_info, *pinfo;
+ u32 total;
+
+ r = -ENODEV;
+ if (!kvm->arch.spp_active)
+ goto out;
+
+ r = -EFAULT;
+ if (copy_from_user(&spp_info, argp, sizeof(spp_info)))
+ goto out;
+
+ r = -EINVAL;
+ if (spp_info.flags != 0 ||
+ spp_info.npages > KVM_SUBPAGE_MAX_PAGES)
+ goto out;
+
+ r = 0;
+ if (!spp_info.npages)
+ goto out;
+
+ total = sizeof(spp_info) +
+ sizeof(spp_info.access_map[0]) * spp_info.npages;
+ pinfo = kvzalloc(total, GFP_KERNEL_ACCOUNT);
+
+ r = -ENOMEM;
+ if (!pinfo)
+ goto out;
+
+ r = -EFAULT;
+ if (copy_from_user(pinfo, argp, total))
+ goto out;
+
+ r = kvm_vm_ioctl_set_subpages(kvm,
+ pinfo->gfn_base,
+ pinfo->npages,
+ pinfo->access_map);
+ kfree(pinfo);
+ break;
+ }
default:
r = -ENOTTY;
}
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index eabd55ec5af7..09e5e8e6e6dd 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -1017,6 +1017,7 @@ struct kvm_ppc_resize_hpt {
#define KVM_CAP_PPC_GUEST_DEBUG_SSTEP 176
#define KVM_CAP_ARM_NISV_TO_USER 177
#define KVM_CAP_ARM_INJECT_EXT_DABT 178
+#define KVM_CAP_X86_SPP 179

#ifdef KVM_CAP_IRQ_ROUTING

@@ -1272,6 +1273,8 @@ struct kvm_vfio_spapr_tce {
struct kvm_userspace_memory_region)
#define KVM_SET_TSS_ADDR _IO(KVMIO, 0x47)
#define KVM_SET_IDENTITY_MAP_ADDR _IOW(KVMIO, 0x48, __u64)
+#define KVM_SUBPAGES_GET_ACCESS _IOR(KVMIO, 0x49, __u64)
+#define KVM_SUBPAGES_SET_ACCESS _IOW(KVMIO, 0x4a, __u64)

/* enable ucontrol for s390 */
struct kvm_s390_ucas_mapping {
--
2.17.2
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