Re: [PATCH v2 05/18] KVM: x86/mmu: use struct kvm_mmu_root_info for mmu->root

Maxim Levitsky
2022-02-23T14:39:16Z

On Thu, 2022-02-17 at 16:03 -0500, Paolo Bonzini wrote:
> The root_hpa and root_pgd fields form essentially a struct kvm_mmu_root_info.
> Use the struct to have more consistency between mmu->root and
> mmu->prev_roots.
>
> The patch is entirely search and replace except for cached_root_available,
> which does not need a temporary struct kvm_mmu_root_info anymore.
>
> Reviewed-by: Sean Christopherson <seanjc@google.com>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
> arch/x86/include/asm/kvm_host.h | 3 +-
> arch/x86/kvm/mmu.h | 4 +-
> arch/x86/kvm/mmu/mmu.c | 69 +++++++++++++++------------------
> arch/x86/kvm/mmu/mmu_audit.c | 4 +-
> arch/x86/kvm/mmu/paging_tmpl.h | 2 +-
> arch/x86/kvm/mmu/tdp_mmu.c | 2 +-
> arch/x86/kvm/mmu/tdp_mmu.h | 2 +-
> arch/x86/kvm/vmx/nested.c | 2 +-
> arch/x86/kvm/vmx/vmx.c | 2 +-
> arch/x86/kvm/x86.c | 2 +-
> 10 files changed, 42 insertions(+), 50 deletions(-)
>
> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
> index 8e512f25a930..6442facfd5c0 100644
> --- a/arch/x86/include/asm/kvm_host.h
> +++ b/arch/x86/include/asm/kvm_host.h
> @@ -432,8 +432,7 @@ struct kvm_mmu {
> int (*sync_page)(struct kvm_vcpu *vcpu,
> struct kvm_mmu_page *sp);
> void (*invlpg)(struct kvm_vcpu *vcpu, gva_t gva, hpa_t root_hpa);
> - hpa_t root_hpa;
> - gpa_t root_pgd;
> + struct kvm_mmu_root_info root;
> union kvm_mmu_role mmu_role;
> u8 root_level;
> u8 shadow_root_level;
> diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h
> index a5a50cfeffff..1d0c1904d69a 100644
> --- a/arch/x86/kvm/mmu.h
> +++ b/arch/x86/kvm/mmu.h
> @@ -85,7 +85,7 @@ void kvm_mmu_sync_prev_roots(struct kvm_vcpu *vcpu);
>
> static inline int kvm_mmu_reload(struct kvm_vcpu *vcpu)
> {
> - if (likely(vcpu->arch.mmu->root_hpa != INVALID_PAGE))
> + if (likely(vcpu->arch.mmu->root.hpa != INVALID_PAGE))
> return 0;
>
> return kvm_mmu_load(vcpu);
> @@ -107,7 +107,7 @@ static inline unsigned long kvm_get_active_pcid(struct kvm_vcpu *vcpu)
>
> static inline void kvm_mmu_load_pgd(struct kvm_vcpu *vcpu)
> {
> - u64 root_hpa = vcpu->arch.mmu->root_hpa;
> + u64 root_hpa = vcpu->arch.mmu->root.hpa;
>
> if (!VALID_PAGE(root_hpa))
> return;
> diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
> index 6ea423b00824..a478667d7561 100644
> --- a/arch/x86/kvm/mmu/mmu.c
> +++ b/arch/x86/kvm/mmu/mmu.c
> @@ -2162,7 +2162,7 @@ static void shadow_walk_init_using_root(struct kvm_shadow_walk_iterator *iterato
> * prev_root is currently only used for 64-bit hosts. So only
> * the active root_hpa is valid here.
> */
> - BUG_ON(root != vcpu->arch.mmu->root_hpa);
> + BUG_ON(root != vcpu->arch.mmu->root.hpa);
>
> iterator->shadow_addr
> = vcpu->arch.mmu->pae_root[(addr >> 30) & 3];
> @@ -2176,7 +2176,7 @@ static void shadow_walk_init_using_root(struct kvm_shadow_walk_iterator *iterato
> static void shadow_walk_init(struct kvm_shadow_walk_iterator *iterator,
> struct kvm_vcpu *vcpu, u64 addr)
> {
> - shadow_walk_init_using_root(iterator, vcpu, vcpu->arch.mmu->root_hpa,
> + shadow_walk_init_using_root(iterator, vcpu, vcpu->arch.mmu->root.hpa,
> addr);
> }
>
> @@ -3245,7 +3245,7 @@ void kvm_mmu_free_roots(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
> BUILD_BUG_ON(KVM_MMU_NUM_PREV_ROOTS >= BITS_PER_LONG);
>
> /* Before acquiring the MMU lock, see if we need to do any real work. */
> - if (!(free_active_root && VALID_PAGE(mmu->root_hpa))) {
> + if (!(free_active_root && VALID_PAGE(mmu->root.hpa))) {
> for (i = 0; i < KVM_MMU_NUM_PREV_ROOTS; i++)
> if ((roots_to_free & KVM_MMU_ROOT_PREVIOUS(i)) &&
> VALID_PAGE(mmu->prev_roots[i].hpa))
> @@ -3265,7 +3265,7 @@ void kvm_mmu_free_roots(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
> if (free_active_root) {
> if (mmu->shadow_root_level >= PT64_ROOT_4LEVEL &&
> (mmu->root_level >= PT64_ROOT_4LEVEL || mmu->direct_map)) {
> - mmu_free_root_page(kvm, &mmu->root_hpa, &invalid_list);
> + mmu_free_root_page(kvm, &mmu->root.hpa, &invalid_list);
> } else if (mmu->pae_root) {
> for (i = 0; i < 4; ++i) {
> if (!IS_VALID_PAE_ROOT(mmu->pae_root[i]))
> @@ -3276,8 +3276,8 @@ void kvm_mmu_free_roots(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
> mmu->pae_root[i] = INVALID_PAE_ROOT;
> }
> }
> - mmu->root_hpa = INVALID_PAGE;
> - mmu->root_pgd = 0;
> + mmu->root.hpa = INVALID_PAGE;
> + mmu->root.pgd = 0;
> }
>
> kvm_mmu_commit_zap_page(kvm, &invalid_list);
> @@ -3350,10 +3350,10 @@ static int mmu_alloc_direct_roots(struct kvm_vcpu *vcpu)
>
> if (is_tdp_mmu_enabled(vcpu->kvm)) {
> root = kvm_tdp_mmu_get_vcpu_root_hpa(vcpu);
> - mmu->root_hpa = root;
> + mmu->root.hpa = root;
> } else if (shadow_root_level >= PT64_ROOT_4LEVEL) {
> root = mmu_alloc_root(vcpu, 0, 0, shadow_root_level, true);
> - mmu->root_hpa = root;
> + mmu->root.hpa = root;
> } else if (shadow_root_level == PT32E_ROOT_LEVEL) {
> if (WARN_ON_ONCE(!mmu->pae_root)) {
> r = -EIO;
> @@ -3368,15 +3368,15 @@ static int mmu_alloc_direct_roots(struct kvm_vcpu *vcpu)
> mmu->pae_root[i] = root | PT_PRESENT_MASK |
> shadow_me_mask;
> }
> - mmu->root_hpa = __pa(mmu->pae_root);
> + mmu->root.hpa = __pa(mmu->pae_root);
> } else {
> WARN_ONCE(1, "Bad TDP root level = %d\n", shadow_root_level);
> r = -EIO;
> goto out_unlock;
> }
>
> - /* root_pgd is ignored for direct MMUs. */
> - mmu->root_pgd = 0;
> + /* root.pgd is ignored for direct MMUs. */
> + mmu->root.pgd = 0;
> out_unlock:
> write_unlock(&vcpu->kvm->mmu_lock);
> return r;
> @@ -3489,7 +3489,7 @@ static int mmu_alloc_shadow_roots(struct kvm_vcpu *vcpu)
> if (mmu->root_level >= PT64_ROOT_4LEVEL) {
> root = mmu_alloc_root(vcpu, root_gfn, 0,
> mmu->shadow_root_level, false);
> - mmu->root_hpa = root;
> + mmu->root.hpa = root;
> goto set_root_pgd;
> }
>
> @@ -3539,14 +3539,14 @@ static int mmu_alloc_shadow_roots(struct kvm_vcpu *vcpu)
> }
>
> if (mmu->shadow_root_level == PT64_ROOT_5LEVEL)
> - mmu->root_hpa = __pa(mmu->pml5_root);
> + mmu->root.hpa = __pa(mmu->pml5_root);
> else if (mmu->shadow_root_level == PT64_ROOT_4LEVEL)
> - mmu->root_hpa = __pa(mmu->pml4_root);
> + mmu->root.hpa = __pa(mmu->pml4_root);
> else
> - mmu->root_hpa = __pa(mmu->pae_root);
> + mmu->root.hpa = __pa(mmu->pae_root);
>
> set_root_pgd:
> - mmu->root_pgd = root_pgd;
> + mmu->root.pgd = root_pgd;
> out_unlock:
> write_unlock(&vcpu->kvm->mmu_lock);
>
> @@ -3659,13 +3659,13 @@ void kvm_mmu_sync_roots(struct kvm_vcpu *vcpu)
> if (vcpu->arch.mmu->direct_map)
> return;
>
> - if (!VALID_PAGE(vcpu->arch.mmu->root_hpa))
> + if (!VALID_PAGE(vcpu->arch.mmu->root.hpa))
> return;
>
> vcpu_clear_mmio_info(vcpu, MMIO_GVA_ANY);
>
> if (vcpu->arch.mmu->root_level >= PT64_ROOT_4LEVEL) {
> - hpa_t root = vcpu->arch.mmu->root_hpa;
> + hpa_t root = vcpu->arch.mmu->root.hpa;
> sp = to_shadow_page(root);
>
> if (!is_unsync_root(root))
> @@ -3956,7 +3956,7 @@ static bool kvm_faultin_pfn(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault,
> static bool is_page_fault_stale(struct kvm_vcpu *vcpu,
> struct kvm_page_fault *fault, int mmu_seq)
> {
> - struct kvm_mmu_page *sp = to_shadow_page(vcpu->arch.mmu->root_hpa);
> + struct kvm_mmu_page *sp = to_shadow_page(vcpu->arch.mmu->root.hpa);
>
> /* Special roots, e.g. pae_root, are not backed by shadow pages. */
> if (sp && is_obsolete_sp(vcpu->kvm, sp))
> @@ -4113,34 +4113,27 @@ static inline bool is_root_usable(struct kvm_mmu_root_info *root, gpa_t pgd,
> /*
> * Find out if a previously cached root matching the new pgd/role is available.
> * The current root is also inserted into the cache.
> - * If a matching root was found, it is assigned to kvm_mmu->root_hpa and true is
> + * If a matching root was found, it is assigned to kvm_mmu->root.hpa and true is
> * returned.
> - * Otherwise, the LRU root from the cache is assigned to kvm_mmu->root_hpa and
> + * Otherwise, the LRU root from the cache is assigned to kvm_mmu->root.hpa and
> * false is returned. This root should now be freed by the caller.
> */
> static bool cached_root_available(struct kvm_vcpu *vcpu, gpa_t new_pgd,
> union kvm_mmu_page_role new_role)
> {
> uint i;
> - struct kvm_mmu_root_info root;
> struct kvm_mmu *mmu = vcpu->arch.mmu;
>
> - root.pgd = mmu->root_pgd;
> - root.hpa = mmu->root_hpa;
> -
> - if (is_root_usable(&root, new_pgd, new_role))
> + if (is_root_usable(&mmu->root, new_pgd, new_role))
> return true;
>
> for (i = 0; i < KVM_MMU_NUM_PREV_ROOTS; i++) {
> - swap(root, mmu->prev_roots[i]);
> + swap(mmu->root, mmu->prev_roots[i]);
>
> - if (is_root_usable(&root, new_pgd, new_role))
> + if (is_root_usable(&mmu->root, new_pgd, new_role))
> break;
> }
>
> - mmu->root_hpa = root.hpa;
> - mmu->root_pgd = root.pgd;
> -
> return i < KVM_MMU_NUM_PREV_ROOTS;
> }
>
> @@ -4196,7 +4189,7 @@ static void __kvm_mmu_new_pgd(struct kvm_vcpu *vcpu, gpa_t new_pgd,
> */
> if (!new_role.direct)
> __clear_sp_write_flooding_count(
> - to_shadow_page(vcpu->arch.mmu->root_hpa));
> + to_shadow_page(vcpu->arch.mmu->root.hpa));
> }
>
> void kvm_mmu_new_pgd(struct kvm_vcpu *vcpu, gpa_t new_pgd)
> @@ -5092,7 +5085,7 @@ static void __kvm_mmu_unload(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu)
> {
> int i;
> kvm_mmu_free_roots(vcpu, mmu, KVM_MMU_ROOTS_ALL);
> - WARN_ON(VALID_PAGE(mmu->root_hpa));
> + WARN_ON(VALID_PAGE(mmu->root.hpa));
> if (mmu->pae_root) {
> for (i = 0; i < 4; ++i)
> WARN_ON(IS_VALID_PAE_ROOT(mmu->pae_root[i]));
> @@ -5287,7 +5280,7 @@ int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, u64 error_code,
> int r, emulation_type = EMULTYPE_PF;
> bool direct = vcpu->arch.mmu->direct_map;
>
> - if (WARN_ON(!VALID_PAGE(vcpu->arch.mmu->root_hpa)))
> + if (WARN_ON(!VALID_PAGE(vcpu->arch.mmu->root.hpa)))
> return RET_PF_RETRY;
>
> r = RET_PF_INVALID;
> @@ -5359,7 +5352,7 @@ void kvm_mmu_invalidate_gva(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
> return;
>
> if (root_hpa == INVALID_PAGE) {
> - mmu->invlpg(vcpu, gva, mmu->root_hpa);
> + mmu->invlpg(vcpu, gva, mmu->root.hpa);
>
> /*
> * INVLPG is required to invalidate any global mappings for the VA,
> @@ -5395,7 +5388,7 @@ void kvm_mmu_invpcid_gva(struct kvm_vcpu *vcpu, gva_t gva, unsigned long pcid)
> uint i;
>
> if (pcid == kvm_get_active_pcid(vcpu)) {
> - mmu->invlpg(vcpu, gva, mmu->root_hpa);
> + mmu->invlpg(vcpu, gva, mmu->root.hpa);
> tlb_flush = true;
> }
>
> @@ -5508,8 +5501,8 @@ static int __kvm_mmu_create(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu)
> struct page *page;
> int i;
>
> - mmu->root_hpa = INVALID_PAGE;
> - mmu->root_pgd = 0;
> + mmu->root.hpa = INVALID_PAGE;
> + mmu->root.pgd = 0;
> for (i = 0; i < KVM_MMU_NUM_PREV_ROOTS; i++)
> mmu->prev_roots[i] = KVM_MMU_ROOT_INFO_INVALID;
>
> diff --git a/arch/x86/kvm/mmu/mmu_audit.c b/arch/x86/kvm/mmu/mmu_audit.c
> index f31fdb874f1f..3e5d62a25350 100644
> --- a/arch/x86/kvm/mmu/mmu_audit.c
> +++ b/arch/x86/kvm/mmu/mmu_audit.c
> @@ -56,11 +56,11 @@ static void mmu_spte_walk(struct kvm_vcpu *vcpu, inspect_spte_fn fn)
> int i;
> struct kvm_mmu_page *sp;
>
> - if (!VALID_PAGE(vcpu->arch.mmu->root_hpa))
> + if (!VALID_PAGE(vcpu->arch.mmu->root.hpa))
> return;
>
> if (vcpu->arch.mmu->root_level >= PT64_ROOT_4LEVEL) {
> - hpa_t root = vcpu->arch.mmu->root_hpa;
> + hpa_t root = vcpu->arch.mmu->root.hpa;
>
> sp = to_shadow_page(root);
> __mmu_spte_walk(vcpu, sp, fn, vcpu->arch.mmu->root_level);
> diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h
> index 5b5bdac97c7b..346f3bad3cb9 100644
> --- a/arch/x86/kvm/mmu/paging_tmpl.h
> +++ b/arch/x86/kvm/mmu/paging_tmpl.h
> @@ -668,7 +668,7 @@ static int FNAME(fetch)(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault,
> if (FNAME(gpte_changed)(vcpu, gw, top_level))
> goto out_gpte_changed;
>
> - if (WARN_ON(!VALID_PAGE(vcpu->arch.mmu->root_hpa)))
> + if (WARN_ON(!VALID_PAGE(vcpu->arch.mmu->root.hpa)))
> goto out_gpte_changed;
>
> for (shadow_walk_init(&it, vcpu, fault->addr);
> diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
> index 8def8f810cb0..debf08212f12 100644
> --- a/arch/x86/kvm/mmu/tdp_mmu.c
> +++ b/arch/x86/kvm/mmu/tdp_mmu.c
> @@ -657,7 +657,7 @@ static inline void tdp_mmu_set_spte_no_dirty_log(struct kvm *kvm,
> else
>
> #define tdp_mmu_for_each_pte(_iter, _mmu, _start, _end) \
> - for_each_tdp_pte(_iter, to_shadow_page(_mmu->root_hpa), _start, _end)
> + for_each_tdp_pte(_iter, to_shadow_page(_mmu->root.hpa), _start, _end)
>
> /*
> * Yield if the MMU lock is contended or this thread needs to return control
> diff --git a/arch/x86/kvm/mmu/tdp_mmu.h b/arch/x86/kvm/mmu/tdp_mmu.h
> index 3f987785702a..57c73d8f76ce 100644
> --- a/arch/x86/kvm/mmu/tdp_mmu.h
> +++ b/arch/x86/kvm/mmu/tdp_mmu.h
> @@ -95,7 +95,7 @@ static inline bool is_tdp_mmu_page(struct kvm_mmu_page *sp) { return sp->tdp_mmu
> static inline bool is_tdp_mmu(struct kvm_mmu *mmu)
> {
> struct kvm_mmu_page *sp;
> - hpa_t hpa = mmu->root_hpa;
> + hpa_t hpa = mmu->root.hpa;
>
> if (WARN_ON(!VALID_PAGE(hpa)))
> return false;
> diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
> index c73e4d938ddc..29289ecca223 100644
> --- a/arch/x86/kvm/vmx/nested.c
> +++ b/arch/x86/kvm/vmx/nested.c
> @@ -5466,7 +5466,7 @@ static int handle_invept(struct kvm_vcpu *vcpu)
> VMXERR_INVALID_OPERAND_TO_INVEPT_INVVPID);
>
> roots_to_free = 0;
> - if (nested_ept_root_matches(mmu->root_hpa, mmu->root_pgd,
> + if (nested_ept_root_matches(mmu->root.hpa, mmu->root.pgd,
> operand.eptp))
> roots_to_free |= KVM_MMU_ROOT_CURRENT;
>
> diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
> index d8547144d3b7..b183dfc41d74 100644
> --- a/arch/x86/kvm/vmx/vmx.c
> +++ b/arch/x86/kvm/vmx/vmx.c
> @@ -2952,7 +2952,7 @@ static inline int vmx_get_current_vpid(struct kvm_vcpu *vcpu)
> static void vmx_flush_tlb_current(struct kvm_vcpu *vcpu)
> {
> struct kvm_mmu *mmu = vcpu->arch.mmu;
> - u64 root_hpa = mmu->root_hpa;
> + u64 root_hpa = mmu->root.hpa;
>
> /* No flush required if the current context is invalid. */
> if (!VALID_PAGE(root_hpa))
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index b912eef5dc1a..c0d7256e3a78 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -762,7 +762,7 @@ bool kvm_inject_emulated_page_fault(struct kvm_vcpu *vcpu,
> if ((fault->error_code & PFERR_PRESENT_MASK) &&
> !(fault->error_code & PFERR_RSVD_MASK))
> kvm_mmu_invalidate_gva(vcpu, fault_mmu, fault->address,
> - fault_mmu->root_hpa);
> + fault_mmu->root.hpa);
>
> fault_mmu->inject_page_fault(vcpu, fault);
> return fault->nested_page_fault;

As a follow up to this patch I suggest that we should also rename pgd to just 'gpa'.

This also brings a question, what pgd acronym actually means?
I guess paging guest directory?

Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>

Best regards,
Maxim Levitsky