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b=ucNSWN+4IDKA/fccgMbM4U22Omvfj/tDBznRkMisyM8RkPZf+zXxGMgzWG23BQnS7z 4smEIlJQ6vwgMfyn1AMTIXF2RGaB23P6CY8yF3w04RFCATJpW9Mv5lzZbHEvzStyE3Ph SKOkVLxXY6heeedQGtDQGKg6rM+WpBC54JlDeyOdN/0gsB71BGzb+eCrnyDn2rCN14zO RtTUn4Tdky+wm2zuwnuyG/NtUd0eMI3wpqNTyHGMw5OEJwj6KUTWdDf/1qnxVXwqMiCF Kp4Ysc2yCGzPYa8/xWyQjimexlUIjSUex+nj4044Gqfe2FdVqN+z643zHoaEoc7FtQVf Zt4g== X-Gm-Message-State: AOJu0YwWNnhdhyTO9cUxaPnhkASVL5O9QV5kCkqxIWp91bZLSKAPzBbx J0Iw1Sg8s9om8ZX+S4tfen+08VUMaXfkFHe6ImiIl/V5YDiq6Ty6iOZdiSdmrA6SmwV4MDXu5eS caQ== X-Google-Smtp-Source: AGHT+IEgY3dn5eo0Xr6pp3rAg0uVd1WuwbDag/Dk23UVvT7MMuxyKVAtWc2T42TlMp1H8D9GJ1Oltmo921o= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:9d:3983:ac13:c240]) (user=seanjc job=sendgmr) by 2002:a05:6a00:8c17:b0:71d:f452:ee99 with SMTP id d2e1a72fcca58-71e1dbcac44mr6866b3a.3.1728584725637; Thu, 10 Oct 2024 11:25:25 -0700 (PDT) Reply-To: Sean Christopherson Date: Thu, 10 Oct 2024 11:23:18 -0700 In-Reply-To: <20241010182427.1434605-1-seanjc@google.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20241010182427.1434605-1-seanjc@google.com> X-Mailer: git-send-email 2.47.0.rc1.288.g06298d1525-goog Message-ID: <20241010182427.1434605-17-seanjc@google.com> Subject: [PATCH v13 16/85] KVM: Replace "async" pointer in gfn=>pfn with "no_wait" and error code From: Sean Christopherson To: Paolo Bonzini , Marc Zyngier , Oliver Upton , Tianrui Zhao , Bibo Mao , Huacai Chen , Michael Ellerman , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Christian Borntraeger , Janosch Frank , Claudio Imbrenda , Sean Christopherson Cc: kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, loongarch@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, " =?utf-8?q?Alex_Benn=C3=A9e?= " , Yan Zhao , David Matlack , David Stevens , Andrew Jones From: David Stevens Add a pfn error code to communicate that hva_to_pfn() failed because I/O was needed and disallowed, and convert @async to a constant @no_wait boolean. This will allow eliminating the @no_wait param by having callers pass in FOLL_NOWAIT along with other FOLL_* flags. Tested-by: Alex Bennée Signed-off-by: David Stevens Co-developed-by: Sean Christopherson Signed-off-by: Sean Christopherson --- arch/x86/kvm/mmu/mmu.c | 18 +++++++++++------- include/linux/kvm_host.h | 3 ++- virt/kvm/kvm_main.c | 27 ++++++++++++++------------- virt/kvm/kvm_mm.h | 2 +- virt/kvm/pfncache.c | 4 ++-- 5 files changed, 30 insertions(+), 24 deletions(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 0e235f276ee5..fa8f3fb7c14b 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -4374,17 +4374,21 @@ static int kvm_faultin_pfn_private(struct kvm_vcpu *vcpu, static int __kvm_faultin_pfn(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault) { - bool async; - if (fault->is_private) return kvm_faultin_pfn_private(vcpu, fault); - async = false; - fault->pfn = __gfn_to_pfn_memslot(fault->slot, fault->gfn, false, &async, + fault->pfn = __gfn_to_pfn_memslot(fault->slot, fault->gfn, false, true, fault->write, &fault->map_writable, &fault->hva); - if (!async) - return RET_PF_CONTINUE; /* *pfn has correct page already */ + + /* + * If resolving the page failed because I/O is needed to fault-in the + * page, then either set up an asynchronous #PF to do the I/O, or if + * doing an async #PF isn't possible, retry with I/O allowed. All + * other failures are terminal, i.e. retrying won't help. + */ + if (fault->pfn != KVM_PFN_ERR_NEEDS_IO) + return RET_PF_CONTINUE; if (!fault->prefetch && kvm_can_do_async_pf(vcpu)) { trace_kvm_try_async_get_page(fault->addr, fault->gfn); @@ -4402,7 +4406,7 @@ static int __kvm_faultin_pfn(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault * to wait for IO. Note, gup always bails if it is unable to quickly * get a page and a fatal signal, i.e. SIGKILL, is pending. */ - fault->pfn = __gfn_to_pfn_memslot(fault->slot, fault->gfn, true, NULL, + fault->pfn = __gfn_to_pfn_memslot(fault->slot, fault->gfn, true, true, fault->write, &fault->map_writable, &fault->hva); return RET_PF_CONTINUE; diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 2faafc7a56ae..071a0a1f1c60 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -97,6 +97,7 @@ #define KVM_PFN_ERR_HWPOISON (KVM_PFN_ERR_MASK + 1) #define KVM_PFN_ERR_RO_FAULT (KVM_PFN_ERR_MASK + 2) #define KVM_PFN_ERR_SIGPENDING (KVM_PFN_ERR_MASK + 3) +#define KVM_PFN_ERR_NEEDS_IO (KVM_PFN_ERR_MASK + 4) /* * error pfns indicate that the gfn is in slot but faild to @@ -1233,7 +1234,7 @@ kvm_pfn_t gfn_to_pfn_prot(struct kvm *kvm, gfn_t gfn, bool write_fault, bool *writable); kvm_pfn_t gfn_to_pfn_memslot(const struct kvm_memory_slot *slot, gfn_t gfn); kvm_pfn_t __gfn_to_pfn_memslot(const struct kvm_memory_slot *slot, gfn_t gfn, - bool interruptible, bool *async, + bool interruptible, bool no_wait, bool write_fault, bool *writable, hva_t *hva); void kvm_release_pfn_clean(kvm_pfn_t pfn); diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 87f81e74cbc0..dd5839abef6c 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -2778,7 +2778,7 @@ static bool hva_to_pfn_fast(unsigned long addr, bool write_fault, * The slow path to get the pfn of the specified host virtual address, * 1 indicates success, -errno is returned if error is detected. */ -static int hva_to_pfn_slow(unsigned long addr, bool *async, bool write_fault, +static int hva_to_pfn_slow(unsigned long addr, bool no_wait, bool write_fault, bool interruptible, bool *writable, kvm_pfn_t *pfn) { /* @@ -2801,7 +2801,7 @@ static int hva_to_pfn_slow(unsigned long addr, bool *async, bool write_fault, if (write_fault) flags |= FOLL_WRITE; - if (async) + if (no_wait) flags |= FOLL_NOWAIT; if (interruptible) flags |= FOLL_INTERRUPTIBLE; @@ -2912,8 +2912,8 @@ static int hva_to_pfn_remapped(struct vm_area_struct *vma, * Pin guest page in memory and return its pfn. * @addr: host virtual address which maps memory to the guest * @interruptible: whether the process can be interrupted by non-fatal signals - * @async: whether this function need to wait IO complete if the - * host page is not in the memory + * @no_wait: whether or not this function need to wait IO complete if the + * host page is not in the memory * @write_fault: whether we should get a writable host page * @writable: whether it allows to map a writable host page for !@write_fault * @@ -2922,7 +2922,7 @@ static int hva_to_pfn_remapped(struct vm_area_struct *vma, * 2): @write_fault = false && @writable, @writable will tell the caller * whether the mapping is writable. */ -kvm_pfn_t hva_to_pfn(unsigned long addr, bool interruptible, bool *async, +kvm_pfn_t hva_to_pfn(unsigned long addr, bool interruptible, bool no_wait, bool write_fault, bool *writable) { struct vm_area_struct *vma; @@ -2934,7 +2934,7 @@ kvm_pfn_t hva_to_pfn(unsigned long addr, bool interruptible, bool *async, if (hva_to_pfn_fast(addr, write_fault, writable, &pfn)) return pfn; - npages = hva_to_pfn_slow(addr, async, write_fault, interruptible, + npages = hva_to_pfn_slow(addr, no_wait, write_fault, interruptible, writable, &pfn); if (npages == 1) return pfn; @@ -2956,16 +2956,17 @@ kvm_pfn_t hva_to_pfn(unsigned long addr, bool interruptible, bool *async, if (r < 0) pfn = KVM_PFN_ERR_FAULT; } else { - if (async && vma_is_valid(vma, write_fault)) - *async = true; - pfn = KVM_PFN_ERR_FAULT; + if (no_wait && vma_is_valid(vma, write_fault)) + pfn = KVM_PFN_ERR_NEEDS_IO; + else + pfn = KVM_PFN_ERR_FAULT; } mmap_read_unlock(current->mm); return pfn; } kvm_pfn_t __gfn_to_pfn_memslot(const struct kvm_memory_slot *slot, gfn_t gfn, - bool interruptible, bool *async, + bool interruptible, bool no_wait, bool write_fault, bool *writable, hva_t *hva) { unsigned long addr = __gfn_to_hva_many(slot, gfn, NULL, write_fault); @@ -2987,21 +2988,21 @@ kvm_pfn_t __gfn_to_pfn_memslot(const struct kvm_memory_slot *slot, gfn_t gfn, writable = NULL; } - return hva_to_pfn(addr, interruptible, async, write_fault, writable); + return hva_to_pfn(addr, interruptible, no_wait, write_fault, writable); } EXPORT_SYMBOL_GPL(__gfn_to_pfn_memslot); kvm_pfn_t gfn_to_pfn_prot(struct kvm *kvm, gfn_t gfn, bool write_fault, bool *writable) { - return __gfn_to_pfn_memslot(gfn_to_memslot(kvm, gfn), gfn, false, NULL, + return __gfn_to_pfn_memslot(gfn_to_memslot(kvm, gfn), gfn, false, false, write_fault, writable, NULL); } EXPORT_SYMBOL_GPL(gfn_to_pfn_prot); kvm_pfn_t gfn_to_pfn_memslot(const struct kvm_memory_slot *slot, gfn_t gfn) { - return __gfn_to_pfn_memslot(slot, gfn, false, NULL, true, NULL, NULL); + return __gfn_to_pfn_memslot(slot, gfn, false, false, true, NULL, NULL); } EXPORT_SYMBOL_GPL(gfn_to_pfn_memslot); diff --git a/virt/kvm/kvm_mm.h b/virt/kvm/kvm_mm.h index a3fa86f60d6c..51f3fee4ca3f 100644 --- a/virt/kvm/kvm_mm.h +++ b/virt/kvm/kvm_mm.h @@ -20,7 +20,7 @@ #define KVM_MMU_UNLOCK(kvm) spin_unlock(&(kvm)->mmu_lock) #endif /* KVM_HAVE_MMU_RWLOCK */ -kvm_pfn_t hva_to_pfn(unsigned long addr, bool interruptible, bool *async, +kvm_pfn_t hva_to_pfn(unsigned long addr, bool interruptible, bool no_wait, bool write_fault, bool *writable); #ifdef CONFIG_HAVE_KVM_PFNCACHE diff --git a/virt/kvm/pfncache.c b/virt/kvm/pfncache.c index 58c706a610e5..32dc61f48c81 100644 --- a/virt/kvm/pfncache.c +++ b/virt/kvm/pfncache.c @@ -197,8 +197,8 @@ static kvm_pfn_t hva_to_pfn_retry(struct gfn_to_pfn_cache *gpc) cond_resched(); } - /* We always request a writeable mapping */ - new_pfn = hva_to_pfn(gpc->uhva, false, NULL, true, NULL); + /* We always request a writable mapping */ + new_pfn = hva_to_pfn(gpc->uhva, false, false, true, NULL); if (is_error_noslot_pfn(new_pfn)) goto out_error;