linux/arch/x86/kvm/svm/svm_onhyperv.h
Paolo Bonzini 3fa5e8fd0a KVM: SVM: delay svm_vcpu_init_msrpm after svm->vmcb is initialized
Right now, svm_hv_vmcb_dirty_nested_enlightenments has an incorrect
dereference of vmcb->control.reserved_sw before the vmcb is checked
for being non-NULL.  The compiler is usually sinking the dereference
after the check; instead of doing this ourselves in the source,
ensure that svm_hv_vmcb_dirty_nested_enlightenments is only called
with a non-NULL VMCB.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Vineeth Pillai <viremana@linux.microsoft.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
[Untested for now due to issues with my AMD machine. - Paolo]
2021-07-27 16:59:00 -04:00

131 lines
3.2 KiB
C

/* SPDX-License-Identifier: GPL-2.0-only */
/*
* KVM L1 hypervisor optimizations on Hyper-V for SVM.
*/
#ifndef __ARCH_X86_KVM_SVM_ONHYPERV_H__
#define __ARCH_X86_KVM_SVM_ONHYPERV_H__
#if IS_ENABLED(CONFIG_HYPERV)
#include <asm/mshyperv.h>
#include "hyperv.h"
#include "kvm_onhyperv.h"
static struct kvm_x86_ops svm_x86_ops;
/*
* Hyper-V uses the software reserved 32 bytes in VMCB
* control area to expose SVM enlightenments to guests.
*/
struct hv_enlightenments {
struct __packed hv_enlightenments_control {
u32 nested_flush_hypercall:1;
u32 msr_bitmap:1;
u32 enlightened_npt_tlb: 1;
u32 reserved:29;
} __packed hv_enlightenments_control;
u32 hv_vp_id;
u64 hv_vm_id;
u64 partition_assist_page;
u64 reserved;
} __packed;
/*
* Hyper-V uses the software reserved clean bit in VMCB
*/
#define VMCB_HV_NESTED_ENLIGHTENMENTS VMCB_SW
int svm_hv_enable_direct_tlbflush(struct kvm_vcpu *vcpu);
static inline void svm_hv_init_vmcb(struct vmcb *vmcb)
{
struct hv_enlightenments *hve =
(struct hv_enlightenments *)vmcb->control.reserved_sw;
if (npt_enabled &&
ms_hyperv.nested_features & HV_X64_NESTED_ENLIGHTENED_TLB)
hve->hv_enlightenments_control.enlightened_npt_tlb = 1;
}
static inline void svm_hv_hardware_setup(void)
{
if (npt_enabled &&
ms_hyperv.nested_features & HV_X64_NESTED_ENLIGHTENED_TLB) {
pr_info("kvm: Hyper-V enlightened NPT TLB flush enabled\n");
svm_x86_ops.tlb_remote_flush = hv_remote_flush_tlb;
svm_x86_ops.tlb_remote_flush_with_range =
hv_remote_flush_tlb_with_range;
}
if (ms_hyperv.nested_features & HV_X64_NESTED_DIRECT_FLUSH) {
int cpu;
pr_info("kvm: Hyper-V Direct TLB Flush enabled\n");
for_each_online_cpu(cpu) {
struct hv_vp_assist_page *vp_ap =
hv_get_vp_assist_page(cpu);
if (!vp_ap)
continue;
vp_ap->nested_control.features.directhypercall = 1;
}
svm_x86_ops.enable_direct_tlbflush =
svm_hv_enable_direct_tlbflush;
}
}
static inline void svm_hv_vmcb_dirty_nested_enlightenments(
struct kvm_vcpu *vcpu)
{
struct vmcb *vmcb = to_svm(vcpu)->vmcb;
struct hv_enlightenments *hve =
(struct hv_enlightenments *)vmcb->control.reserved_sw;
/*
* vmcb can be NULL if called during early vcpu init.
* And its okay not to mark vmcb dirty during vcpu init
* as we mark it dirty unconditionally towards end of vcpu
* init phase.
*/
if (vmcb_is_clean(vmcb, VMCB_HV_NESTED_ENLIGHTENMENTS) &&
hve->hv_enlightenments_control.msr_bitmap)
vmcb_mark_dirty(vmcb, VMCB_HV_NESTED_ENLIGHTENMENTS);
}
static inline void svm_hv_update_vp_id(struct vmcb *vmcb,
struct kvm_vcpu *vcpu)
{
struct hv_enlightenments *hve =
(struct hv_enlightenments *)vmcb->control.reserved_sw;
u32 vp_index = kvm_hv_get_vpindex(vcpu);
if (hve->hv_vp_id != vp_index) {
hve->hv_vp_id = vp_index;
vmcb_mark_dirty(vmcb, VMCB_HV_NESTED_ENLIGHTENMENTS);
}
}
#else
static inline void svm_hv_init_vmcb(struct vmcb *vmcb)
{
}
static inline void svm_hv_hardware_setup(void)
{
}
static inline void svm_hv_vmcb_dirty_nested_enlightenments(
struct kvm_vcpu *vcpu)
{
}
static inline void svm_hv_update_vp_id(struct vmcb *vmcb,
struct kvm_vcpu *vcpu)
{
}
#endif /* CONFIG_HYPERV */
#endif /* __ARCH_X86_KVM_SVM_ONHYPERV_H__ */