linux/arch/x86/kvm/mmu/tdp_mmu.h
Sean Christopherson 6c6e166b2c KVM: x86/mmu: Don't WARN on a NULL shadow page in TDP MMU check
Treat a NULL shadow page in the "is a TDP MMU" check as valid, non-TDP
root.  KVM uses a "direct" PAE paging MMU when TDP is disabled and the
guest is running with paging disabled.  In that case, root_hpa points at
the pae_root page (of which only 32 bytes are used), not a standard
shadow page, and the WARN fires (a lot).

Fixes: 0b873fd7fb ("KVM: x86/mmu: Remove redundant is_tdp_mmu_enabled check")
Cc: David Matlack <dmatlack@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210622072454.3449146-1-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-06-24 11:47:56 -04:00

114 lines
4.1 KiB
C

// SPDX-License-Identifier: GPL-2.0
#ifndef __KVM_X86_MMU_TDP_MMU_H
#define __KVM_X86_MMU_TDP_MMU_H
#include <linux/kvm_host.h>
hpa_t kvm_tdp_mmu_get_vcpu_root_hpa(struct kvm_vcpu *vcpu);
__must_check static inline bool kvm_tdp_mmu_get_root(struct kvm *kvm,
struct kvm_mmu_page *root)
{
if (root->role.invalid)
return false;
return refcount_inc_not_zero(&root->tdp_mmu_root_count);
}
void kvm_tdp_mmu_put_root(struct kvm *kvm, struct kvm_mmu_page *root,
bool shared);
bool __kvm_tdp_mmu_zap_gfn_range(struct kvm *kvm, int as_id, gfn_t start,
gfn_t end, bool can_yield, bool flush,
bool shared);
static inline bool kvm_tdp_mmu_zap_gfn_range(struct kvm *kvm, int as_id,
gfn_t start, gfn_t end, bool flush,
bool shared)
{
return __kvm_tdp_mmu_zap_gfn_range(kvm, as_id, start, end, true, flush,
shared);
}
static inline bool kvm_tdp_mmu_zap_sp(struct kvm *kvm, struct kvm_mmu_page *sp)
{
gfn_t end = sp->gfn + KVM_PAGES_PER_HPAGE(sp->role.level + 1);
/*
* Don't allow yielding, as the caller may have a flush pending. Note,
* if mmu_lock is held for write, zapping will never yield in this case,
* but explicitly disallow it for safety. The TDP MMU does not yield
* until it has made forward progress (steps sideways), and when zapping
* a single shadow page that it's guaranteed to see (thus the mmu_lock
* requirement), its "step sideways" will always step beyond the bounds
* of the shadow page's gfn range and stop iterating before yielding.
*/
lockdep_assert_held_write(&kvm->mmu_lock);
return __kvm_tdp_mmu_zap_gfn_range(kvm, kvm_mmu_page_as_id(sp),
sp->gfn, end, false, false, false);
}
void kvm_tdp_mmu_zap_all(struct kvm *kvm);
void kvm_tdp_mmu_invalidate_all_roots(struct kvm *kvm);
void kvm_tdp_mmu_zap_invalidated_roots(struct kvm *kvm);
int kvm_tdp_mmu_map(struct kvm_vcpu *vcpu, gpa_t gpa, u32 error_code,
int map_writable, int max_level, kvm_pfn_t pfn,
bool prefault);
bool kvm_tdp_mmu_unmap_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range,
bool flush);
bool kvm_tdp_mmu_age_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range);
bool kvm_tdp_mmu_test_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range);
bool kvm_tdp_mmu_set_spte_gfn(struct kvm *kvm, struct kvm_gfn_range *range);
bool kvm_tdp_mmu_wrprot_slot(struct kvm *kvm, struct kvm_memory_slot *slot,
int min_level);
bool kvm_tdp_mmu_clear_dirty_slot(struct kvm *kvm,
struct kvm_memory_slot *slot);
void kvm_tdp_mmu_clear_dirty_pt_masked(struct kvm *kvm,
struct kvm_memory_slot *slot,
gfn_t gfn, unsigned long mask,
bool wrprot);
bool kvm_tdp_mmu_zap_collapsible_sptes(struct kvm *kvm,
const struct kvm_memory_slot *slot,
bool flush);
bool kvm_tdp_mmu_write_protect_gfn(struct kvm *kvm,
struct kvm_memory_slot *slot, gfn_t gfn,
int min_level);
int kvm_tdp_mmu_get_walk(struct kvm_vcpu *vcpu, u64 addr, u64 *sptes,
int *root_level);
#ifdef CONFIG_X86_64
bool kvm_mmu_init_tdp_mmu(struct kvm *kvm);
void kvm_mmu_uninit_tdp_mmu(struct kvm *kvm);
static inline bool is_tdp_mmu_enabled(struct kvm *kvm) { return kvm->arch.tdp_mmu_enabled; }
static inline bool is_tdp_mmu_page(struct kvm_mmu_page *sp) { return sp->tdp_mmu_page; }
static inline bool is_tdp_mmu(struct kvm_mmu *mmu)
{
struct kvm_mmu_page *sp;
hpa_t hpa = mmu->root_hpa;
if (WARN_ON(!VALID_PAGE(hpa)))
return false;
/*
* A NULL shadow page is legal when shadowing a non-paging guest with
* PAE paging, as the MMU will be direct with root_hpa pointing at the
* pae_root page, not a shadow page.
*/
sp = to_shadow_page(hpa);
return sp && is_tdp_mmu_page(sp) && sp->root_count;
}
#else
static inline bool kvm_mmu_init_tdp_mmu(struct kvm *kvm) { return false; }
static inline void kvm_mmu_uninit_tdp_mmu(struct kvm *kvm) {}
static inline bool is_tdp_mmu_enabled(struct kvm *kvm) { return false; }
static inline bool is_tdp_mmu_page(struct kvm_mmu_page *sp) { return false; }
static inline bool is_tdp_mmu(struct kvm_mmu *mmu) { return false; }
#endif
#endif /* __KVM_X86_MMU_TDP_MMU_H */