[PATCH 4.9 17/31] KVM: x86: extend usage of RET_MMIO_PF_* constants

From: Paolo Bonzini pbonzini@redhat.com

commit 9b8ebbdb74b5ad76b9dfd8b101af17839174b126 upstream.

The x86 MMU if full of code that returns 0 and 1 for retry/emulate. Use the existing RET_MMIO_PF_RETRY/RET_MMIO_PF_EMULATE enum, renaming it to drop the MMIO part.

Signed-off-by: Paolo Bonzini pbonzini@redhat.com [bwh: Backported to 4.9: adjust context] Signed-off-by: Ben Hutchings ben@decadent.org.uk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/x86/kvm/mmu.c | 93 +++++++++++++++++++++------------------------ arch/x86/kvm/paging_tmpl.h | 18 ++++---- 2 files changed, 54 insertions(+), 57 deletions(-)

--- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -142,6 +142,20 @@ module_param(dbg, bool, 0644); /* make pte_list_desc fit well in cache line */ #define PTE_LIST_EXT 3

+/* + * Return values of handle_mmio_page_fault and mmu.page_fault: + * RET_PF_RETRY: let CPU fault again on the address. + * RET_PF_EMULATE: mmio page fault, emulate the instruction directly. + * + * For handle_mmio_page_fault only: + * RET_PF_INVALID: the spte is invalid, let the real page fault path update it. + */ +enum { + RET_PF_RETRY = 0, + RET_PF_EMULATE = 1, + RET_PF_INVALID = 2, +}; + struct pte_list_desc { u64 *sptes[PTE_LIST_EXT]; struct pte_list_desc *more; @@ -2598,13 +2612,13 @@ done: return ret; }

-static bool mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep, unsigned pte_access, - int write_fault, int level, gfn_t gfn, kvm_pfn_t pfn, - bool speculative, bool host_writable) +static int mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep, unsigned pte_access, + int write_fault, int level, gfn_t gfn, kvm_pfn_t pfn, + bool speculative, bool host_writable) { int was_rmapped = 0; int rmap_count; - bool emulate = false; + int ret = RET_PF_RETRY;

pgprintk("%s: spte %llx write_fault %d gfn %llx\n", __func__, *sptep, write_fault, gfn); @@ -2634,12 +2648,12 @@ static bool mmu_set_spte(struct kvm_vcpu if (set_spte(vcpu, sptep, pte_access, level, gfn, pfn, speculative, true, host_writable)) { if (write_fault) - emulate = true; + ret = RET_PF_EMULATE; kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu); }

if (unlikely(is_mmio_spte(*sptep))) - emulate = true; + ret = RET_PF_EMULATE;

pgprintk("%s: setting spte %llx\n", __func__, *sptep); pgprintk("instantiating %s PTE (%s) at %llx (%llx) addr %p\n", @@ -2659,7 +2673,7 @@ static bool mmu_set_spte(struct kvm_vcpu

kvm_release_pfn_clean(pfn);

- return emulate; + return ret; }

static kvm_pfn_t pte_prefetch_gfn_to_pfn(struct kvm_vcpu *vcpu, gfn_t gfn, @@ -2798,14 +2812,13 @@ static int kvm_handle_bad_page(struct kv * Do not cache the mmio info caused by writing the readonly gfn * into the spte otherwise read access on readonly gfn also can * caused mmio page fault and treat it as mmio access. - * Return 1 to tell kvm to emulate it. */ if (pfn == KVM_PFN_ERR_RO_FAULT) - return 1; + return RET_PF_EMULATE;

if (pfn == KVM_PFN_ERR_HWPOISON) { kvm_send_hwpoison_signal(kvm_vcpu_gfn_to_hva(vcpu, gfn), current); - return 0; + return RET_PF_RETRY; }

return -EFAULT; @@ -3031,13 +3044,13 @@ static int nonpaging_map(struct kvm_vcpu }

if (fast_page_fault(vcpu, v, level, error_code)) - return 0; + return RET_PF_RETRY;

mmu_seq = vcpu->kvm->mmu_notifier_seq; smp_rmb();

if (try_async_pf(vcpu, prefault, gfn, v, &pfn, write, &map_writable)) - return 0; + return RET_PF_RETRY;

if (handle_abnormal_pfn(vcpu, v, gfn, pfn, ACC_ALL, &r)) return r; @@ -3056,7 +3069,7 @@ static int nonpaging_map(struct kvm_vcpu out_unlock: spin_unlock(&vcpu->kvm->mmu_lock); kvm_release_pfn_clean(pfn); - return 0; + return RET_PF_RETRY; }

@@ -3383,54 +3396,38 @@ exit: return reserved; }

-/* - * Return values of handle_mmio_page_fault: - * RET_MMIO_PF_EMULATE: it is a real mmio page fault, emulate the instruction - * directly. - * RET_MMIO_PF_INVALID: invalid spte is detected then let the real page - * fault path update the mmio spte. - * RET_MMIO_PF_RETRY: let CPU fault again on the address. - * RET_MMIO_PF_BUG: a bug was detected (and a WARN was printed). - */ -enum { - RET_MMIO_PF_EMULATE = 1, - RET_MMIO_PF_INVALID = 2, - RET_MMIO_PF_RETRY = 0, - RET_MMIO_PF_BUG = -1 -}; - static int handle_mmio_page_fault(struct kvm_vcpu *vcpu, u64 addr, bool direct) { u64 spte; bool reserved;

if (mmio_info_in_cache(vcpu, addr, direct)) - return RET_MMIO_PF_EMULATE; + return RET_PF_EMULATE;

reserved = walk_shadow_page_get_mmio_spte(vcpu, addr, &spte); if (WARN_ON(reserved)) - return RET_MMIO_PF_BUG; + return -EINVAL;

if (is_mmio_spte(spte)) { gfn_t gfn = get_mmio_spte_gfn(spte); unsigned access = get_mmio_spte_access(spte);

if (!check_mmio_spte(vcpu, spte)) - return RET_MMIO_PF_INVALID; + return RET_PF_INVALID;

if (direct) addr = 0;

trace_handle_mmio_page_fault(addr, gfn, access); vcpu_cache_mmio_info(vcpu, addr, gfn, access); - return RET_MMIO_PF_EMULATE; + return RET_PF_EMULATE; }

/* * If the page table is zapped by other cpus, let CPU fault again on * the address. */ - return RET_MMIO_PF_RETRY; + return RET_PF_RETRY; } EXPORT_SYMBOL_GPL(handle_mmio_page_fault);

@@ -3480,7 +3477,7 @@ static int nonpaging_page_fault(struct k pgprintk("%s: gva %lx error %x\n", __func__, gva, error_code);

if (page_fault_handle_page_track(vcpu, error_code, gfn)) - return 1; + return RET_PF_EMULATE;

r = mmu_topup_memory_caches(vcpu); if (r) @@ -3568,7 +3565,7 @@ static int tdp_page_fault(struct kvm_vcp MMU_WARN_ON(!VALID_PAGE(vcpu->arch.mmu.root_hpa));

if (page_fault_handle_page_track(vcpu, error_code, gfn)) - return 1; + return RET_PF_EMULATE;

r = mmu_topup_memory_caches(vcpu); if (r) @@ -3585,13 +3582,13 @@ static int tdp_page_fault(struct kvm_vcp }

if (fast_page_fault(vcpu, gpa, level, error_code)) - return 0; + return RET_PF_RETRY;

mmu_seq = vcpu->kvm->mmu_notifier_seq; smp_rmb();

if (try_async_pf(vcpu, prefault, gfn, gpa, &pfn, write, &map_writable)) - return 0; + return RET_PF_RETRY;

if (handle_abnormal_pfn(vcpu, 0, gfn, pfn, ACC_ALL, &r)) return r; @@ -3610,7 +3607,7 @@ static int tdp_page_fault(struct kvm_vcp out_unlock: spin_unlock(&vcpu->kvm->mmu_lock); kvm_release_pfn_clean(pfn); - return 0; + return RET_PF_RETRY; }

static void nonpaging_init_context(struct kvm_vcpu *vcpu, @@ -4526,24 +4523,24 @@ int kvm_mmu_page_fault(struct kvm_vcpu * enum emulation_result er; bool direct = vcpu->arch.mmu.direct_map || mmu_is_nested(vcpu);

+ r = RET_PF_INVALID; if (unlikely(error_code & PFERR_RSVD_MASK)) { r = handle_mmio_page_fault(vcpu, cr2, direct); - if (r == RET_MMIO_PF_EMULATE) { + if (r == RET_PF_EMULATE) { emulation_type = 0; goto emulate; } - if (r == RET_MMIO_PF_RETRY) - return 1; - if (r < 0) - return r; - /* Must be RET_MMIO_PF_INVALID. */ }

- r = vcpu->arch.mmu.page_fault(vcpu, cr2, error_code, false); + if (r == RET_PF_INVALID) { + r = vcpu->arch.mmu.page_fault(vcpu, cr2, error_code, false); + WARN_ON(r == RET_PF_INVALID); + } + + if (r == RET_PF_RETRY) + return 1; if (r < 0) return r; - if (!r) - return 1;

if (mmio_info_in_cache(vcpu, cr2, direct)) emulation_type = 0; --- a/arch/x86/kvm/paging_tmpl.h +++ b/arch/x86/kvm/paging_tmpl.h @@ -577,7 +577,7 @@ static int FNAME(fetch)(struct kvm_vcpu struct kvm_mmu_page *sp = NULL; struct kvm_shadow_walk_iterator it; unsigned direct_access, access = gw->pt_access; - int top_level, emulate; + int top_level, ret;

direct_access = gw->pte_access;

@@ -643,15 +643,15 @@ static int FNAME(fetch)(struct kvm_vcpu }

clear_sp_write_flooding_count(it.sptep); - emulate = mmu_set_spte(vcpu, it.sptep, gw->pte_access, write_fault, - it.level, gw->gfn, pfn, prefault, map_writable); + ret = mmu_set_spte(vcpu, it.sptep, gw->pte_access, write_fault, + it.level, gw->gfn, pfn, prefault, map_writable); FNAME(pte_prefetch)(vcpu, gw, it.sptep);

- return emulate; + return ret;

out_gpte_changed: kvm_release_pfn_clean(pfn); - return 0; + return RET_PF_RETRY; }

/* @@ -746,12 +746,12 @@ static int FNAME(page_fault)(struct kvm_ if (!prefault) inject_page_fault(vcpu, &walker.fault);

- return 0; + return RET_PF_RETRY; }

if (page_fault_handle_page_track(vcpu, error_code, walker.gfn)) { shadow_page_table_clear_flood(vcpu, addr); - return 1; + return RET_PF_EMULATE; }

vcpu->arch.write_fault_to_shadow_pgtable = false; @@ -773,7 +773,7 @@ static int FNAME(page_fault)(struct kvm_

if (try_async_pf(vcpu, prefault, walker.gfn, addr, &pfn, write_fault, &map_writable)) - return 0; + return RET_PF_RETRY;

if (handle_abnormal_pfn(vcpu, mmu_is_nested(vcpu) ? 0 : addr, walker.gfn, pfn, walker.pte_access, &r)) @@ -818,7 +818,7 @@ static int FNAME(page_fault)(struct kvm_ out_unlock: spin_unlock(&vcpu->kvm->mmu_lock); kvm_release_pfn_clean(pfn); - return 0; + return RET_PF_RETRY; }

static gpa_t FNAME(get_level1_sp_gpa)(struct kvm_mmu_page *sp)