From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7E8534446E7 for ; Thu, 16 Jul 2026 18:15:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784225716; cv=none; b=QA/TH1wenJiwRCIjVKlM9Fck/Njh3N9+d8CE5HKeEfk48fv4VwgM/ZFs2auGEspwa+3htlRiFSNPS/b3V0KBqoUAWXGV1kMCUYk9BwI/xW6rzCUTCS4PeSqfP1fjxmlu/a4UQzqpLZMegKGIrO1LsS3BYmQJWoaiYDVLXQHm0yY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784225716; c=relaxed/simple; bh=FmJzLb+n+bJ8qEVB8q4rI758/WTEOrbdo3jqTnz2IHg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=iBf4PxVIXifJQKCqi4/5N7UwtC1hDQ/FWMiHo6NHDU3cBlzCqWwOuiaSMmSxBz0UiOvS+heJ8bPcToJuwlVt7WGQGcH5gymcfmfErmmnvG7pOCO/VsiCGnANsZIqzIP2W1ipUUJEmKcA/V6Fil+17uYziq2d9elgmSvuaJAHbyg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=KPMX2bLC; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="KPMX2bLC" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1784225709; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=u0+M/PykJDVqAjN7ZHI2LjwPbsl16uAh/kMFqVLU5gQ=; b=KPMX2bLCKzhHG5WujiYpCPTfd5GgB5DamrU5zDZcetRtRLX1NPyS/XW4Zb3EC2sS0sS4x9 ZsMXxw+gT4i0sKmpmGxZhx/yvsDBazP4+XS0PjXp+Lf0rtzoxIBpXAPh3ujAYfI1LbgHsQ 3LNsgBUrVigIv6XiRkKMZKhA5C2z8zk= Received: from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-507-HyLXb4zROBqgkmG2Z3V9kA-1; Thu, 16 Jul 2026 14:15:07 -0400 X-MC-Unique: HyLXb4zROBqgkmG2Z3V9kA-1 X-Mimecast-MFC-AGG-ID: HyLXb4zROBqgkmG2Z3V9kA_1784225706 Received: from mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.93]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 90755180062C; Thu, 16 Jul 2026 18:15:06 +0000 (UTC) Received: from virtlab1023.lab.eng.rdu2.redhat.lab.eng.rdu2.redhat.com (virtlab1023.lab.eng.rdu2.redhat.com [10.8.1.187]) by mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 20C401800480; Thu, 16 Jul 2026 18:15:06 +0000 (UTC) From: Paolo Bonzini To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: nsaenz@amazon.com Subject: [PATCH 13/24] KVM: Introduce kvm_check_gen()/kvm_memslots_check_gen() Date: Thu, 16 Jul 2026 14:14:45 -0400 Message-ID: <20260716181456.402786-14-pbonzini@redhat.com> In-Reply-To: <20260716181456.402786-1-pbonzini@redhat.com> References: <20260716181456.402786-1-pbonzini@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 In many cases, retrieving kvm_memslots is followed by a check on the generation of the slots. Introduce a helper function that either does the check alone, or compounds it with returning the struct kvm_memslots* to the caller. Signed-off-by: Paolo Bonzini --- arch/x86/kvm/x86.c | 10 ++-------- include/linux/kvm_host.h | 12 ++++++++++++ virt/kvm/kvm_main.c | 8 ++++---- virt/kvm/pfncache.c | 10 ++++------ 4 files changed, 22 insertions(+), 18 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index e2240f817c22..58f544df47e1 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -2032,7 +2032,6 @@ static void record_steal_time(struct kvm_vcpu *vcpu) { struct gfn_to_hva_cache *ghc = &vcpu->arch.st.cache; struct kvm_steal_time __user *st; - struct kvm_memslots *slots; gpa_t gpa = vcpu->arch.st.msr_val & KVM_STEAL_VALID_BITS; u64 steal; u32 version; @@ -2048,9 +2047,7 @@ static void record_steal_time(struct kvm_vcpu *vcpu) if (WARN_ON_ONCE(current->mm != vcpu->kvm->mm)) return; - slots = kvm_memslots(vcpu->kvm); - - if (unlikely(slots->generation != ghc->generation || + if (unlikely(!kvm_check_gen(vcpu->kvm, ghc->generation) || gpa != ghc->gpa || kvm_is_error_hva(ghc->hva) || !ghc->memslot)) { /* We rely on the fact that it fits in a single page. */ @@ -2601,7 +2598,6 @@ static void kvm_steal_time_set_preempted(struct kvm_vcpu *vcpu) { struct gfn_to_hva_cache *ghc = &vcpu->arch.st.cache; struct kvm_steal_time __user *st; - struct kvm_memslots *slots; static const u8 preempted = KVM_VCPU_PREEMPTED; gpa_t gpa = vcpu->arch.st.msr_val & KVM_STEAL_VALID_BITS; @@ -2628,9 +2624,7 @@ static void kvm_steal_time_set_preempted(struct kvm_vcpu *vcpu) if (unlikely(current->mm != vcpu->kvm->mm)) return; - slots = kvm_memslots(vcpu->kvm); - - if (unlikely(slots->generation != ghc->generation || + if (unlikely(!kvm_check_gen(vcpu->kvm, ghc->generation) || gpa != ghc->gpa || kvm_is_error_hva(ghc->hva) || !ghc->memslot)) return; diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 341f2e97f3cb..122af87d6f9a 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -2559,6 +2559,18 @@ static inline bool kvm_mem_attributes_may_exec(u64 attrs) return !(attrs & KVM_MEMORY_ATTRIBUTE_NX); } +static inline bool kvm_memslots_check_gen(struct kvm *kvm, u64 slots_generation, struct kvm_memslots **p_slots) +{ + struct kvm_memslots *slots = *p_slots = kvm_memslots(kvm); + return slots->generation == slots_generation; +} + +static inline bool kvm_check_gen(struct kvm *kvm, u64 slots_generation) +{ + struct kvm_memslots *slots; + return kvm_memslots_check_gen(kvm, slots_generation, &slots); +} + #ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES #define KVM_MEMORY_ATTRIBUTE_PROT \ (KVM_MEMORY_ATTRIBUTE_NR | KVM_MEMORY_ATTRIBUTE_NW | KVM_MEMORY_ATTRIBUTE_NX) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 20113069562e..1afaec56ecb3 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -3502,14 +3502,14 @@ int kvm_write_guest_offset_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc, void *data, unsigned int offset, unsigned long len) { - struct kvm_memslots *slots = kvm_memslots(kvm); + struct kvm_memslots *slots; int r; gpa_t gpa = ghc->gpa + offset; if (WARN_ON_ONCE(len + offset > ghc->len)) return -EINVAL; - if (slots->generation != ghc->generation) { + if (unlikely(!kvm_memslots_check_gen(kvm, ghc->generation, &slots))) { if (__kvm_gfn_to_hva_cache_init(slots, ghc, ghc->gpa, ghc->len)) return -EFAULT; } @@ -3540,14 +3540,14 @@ int kvm_read_guest_offset_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc, void *data, unsigned int offset, unsigned long len) { - struct kvm_memslots *slots = kvm_memslots(kvm); + struct kvm_memslots *slots; int r; gpa_t gpa = ghc->gpa + offset; if (WARN_ON_ONCE(len + offset > ghc->len)) return -EINVAL; - if (slots->generation != ghc->generation) { + if (unlikely(!kvm_memslots_check_gen(kvm, ghc->generation, &slots))) { if (__kvm_gfn_to_hva_cache_init(slots, ghc, ghc->gpa, ghc->len)) return -EFAULT; } diff --git a/virt/kvm/pfncache.c b/virt/kvm/pfncache.c index 728d2c1b488a..e09703d249bb 100644 --- a/virt/kvm/pfncache.c +++ b/virt/kvm/pfncache.c @@ -72,8 +72,6 @@ static bool kvm_gpc_is_valid_len(gpa_t gpa, unsigned long uhva, bool kvm_gpc_check(struct gfn_to_pfn_cache *gpc, unsigned long len) { - struct kvm_memslots *slots = kvm_memslots(gpc->kvm); - if (!gpc->active) return false; @@ -81,7 +79,7 @@ bool kvm_gpc_check(struct gfn_to_pfn_cache *gpc, unsigned long len) * If the page was cached from a memslot, make sure the memslots have * not been re-configured. */ - if (!kvm_is_error_gpa(gpc->gpa) && gpc->generation != slots->generation) + if (!kvm_is_error_gpa(gpc->gpa) && !kvm_check_gen(gpc->kvm, gpc->generation)) return false; if (kvm_is_error_hva(gpc->uhva)) @@ -290,12 +288,12 @@ static int __kvm_gpc_refresh(struct gfn_to_pfn_cache *gpc, gpa_t gpa, unsigned l if (gpc->uhva != old_uhva) hva_change = true; } else { - struct kvm_memslots *slots = kvm_memslots(gpc->kvm); + struct kvm_memslots *slots; page_offset = offset_in_page(gpa); - if (gpc->gpa != gpa || gpc->generation != slots->generation || - kvm_is_error_hva(gpc->uhva)) { + if (!kvm_memslots_check_gen(gpc->kvm, gpc->generation, &slots) || + gpc->gpa != gpa || kvm_is_error_hva(gpc->uhva)) { gfn_t gfn = gpa_to_gfn(gpa); gpc->gpa = gpa; -- 2.52.0