From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 82B3BCDB479 for ; Wed, 24 Jun 2026 16:01:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=1TizSR+F7DAiTkrpTXeVx6qQOYtrq2iNJ5sQ0l7hR80=; b=H1cIz0OS0EEkK2N2Hqa96SCza7 qyrUkgiqRbj4UHcx6G7VsX11TUZ77kT7eBPFTWsHHIkxwhrawhNyawq1RAXn7xPcmFFEMwOPb6jPb gyR6tOVGsLNhJRFC3RQYayCLcV8ahYvXamuj10DwyGaZTcz/JMFynzytze+KRfCqTv094Q/5GOkOv gPk+I8XRKSBWtonuPERD29p8DCIeOAEoiFBD1//FEVodlVpsmFxvvOULxJ5xSiiyeTq3UMCWk+/9B OYVIWIB1XO4eJKNasenCu4lfMq9Gb0zeOW8WH8+uWFnTEU/KUJ+kLqJ2yg20lYFcM5aC/PztBkMrB XM9ZsbZA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wcQ2J-000000084ZL-0dPL; Wed, 24 Jun 2026 16:01:11 +0000 Received: from confino.investici.org ([2a11:7980:1::2:0]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wcQ2D-000000084UG-1SOT for linux-arm-kernel@lists.infradead.org; Wed, 24 Jun 2026 16:01:07 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=grrlz.net; s=stigmate; t=1782316852; bh=1TizSR+F7DAiTkrpTXeVx6qQOYtrq2iNJ5sQ0l7hR80=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=GExjL+0gBG861De2/4YrEV8wzoyVq+05CzBbBuEiEwsoVtpj0hoFq4D0MDcZGwqCW IKPYqIXolFbPVC6hg+C8s5+xISsOAyLV4U1mcYiO3l1OQzGmWC432DcwDsDz3iY9jW JN46z0sRYognTEUCKHPFgPA/XOxGy/012uVPiWds= Received: from mx1.investici.org (unknown [127.0.0.1]) by confino.investici.org (Postfix) with ESMTP id 4glmr41MYMz10tp; Wed, 24 Jun 2026 16:00:52 +0000 (UTC) Received: by mx1.investici.org (Postfix) id 4glmr240Xlz10tb; Wed, 24 Jun 2026 16:00:50 +0000 (UTC) From: Bradley Morgan To: Marc Zyngier , Oliver Upton Cc: Fuad Tabba , Joey Gouly , Steffen Eiden , Suzuki K Poulose , Zenghui Yu , Catalin Marinas , Will Deacon , Quentin Perret , Vincent Donnefort , Gavin Shan , Alexandru Elisei , linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org, Bradley Morgan Subject: [PATCH v3 1/3] KVM: arm64: skip pKVM cache flushes for non cacheable mappings Date: Wed, 24 Jun 2026 16:00:26 +0000 Message-ID: <20260624160028.15591-2-include@grrlz.net> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260624160028.15591-1-include@grrlz.net> References: <20260624160028.15591-1-include@grrlz.net> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260624_090105_528284_E080CFC8 X-CRM114-Status: GOOD ( 13.79 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org pKVM keeps its own mapping list for stage 2 operations. Its flush path uses that list directly, so it lost the PTE attribute check done by the generic stage 2 walker. Record whether a mapping is cacheable and skip cache maintenance for mappings that are not cacheable. Fixes: e912efed485a ("KVM: arm64: Introduce the EL1 pKVM MMU") Signed-off-by: Bradley Morgan --- arch/arm64/kvm/pkvm.c | 51 ++++++++++++++++++++++++++++++++++--------- 1 file changed, 41 insertions(+), 10 deletions(-) diff --git a/arch/arm64/kvm/pkvm.c b/arch/arm64/kvm/pkvm.c index 428723b1b0f5..ca6e823028c2 100644 --- a/arch/arm64/kvm/pkvm.c +++ b/arch/arm64/kvm/pkvm.c @@ -302,9 +302,32 @@ static u64 __pkvm_mapping_start(struct pkvm_mapping *m) return m->gfn * PAGE_SIZE; } +#define PKVM_MAPPING_NR_PAGES_MASK GENMASK_ULL(47, 0) +#define PKVM_MAPPING_CACHEABLE BIT_ULL(48) + +static u64 pkvm_mapping_nr_pages(struct pkvm_mapping *m) +{ + return m->nr_pages & PKVM_MAPPING_NR_PAGES_MASK; +} + +static bool pkvm_mapping_is_cacheable(struct pkvm_mapping *m) +{ + return m->nr_pages & PKVM_MAPPING_CACHEABLE; +} + +static void pkvm_mapping_set_nr_pages(struct pkvm_mapping *m, u64 nr_pages, + bool cacheable) +{ + WARN_ON_ONCE(nr_pages & ~PKVM_MAPPING_NR_PAGES_MASK); + + m->nr_pages = nr_pages & PKVM_MAPPING_NR_PAGES_MASK; + if (cacheable) + m->nr_pages |= PKVM_MAPPING_CACHEABLE; +} + static u64 __pkvm_mapping_end(struct pkvm_mapping *m) { - return (m->gfn + m->nr_pages) * PAGE_SIZE - 1; + return (m->gfn + pkvm_mapping_nr_pages(m)) * PAGE_SIZE - 1; } INTERVAL_TREE_DEFINE(struct pkvm_mapping, node, u64, __subtree_last, @@ -350,7 +373,7 @@ static int __pkvm_pgtable_stage2_reclaim(struct kvm_pgtable *pgt, u64 start, u64 continue; page = pfn_to_page(mapping->pfn); - WARN_ON_ONCE(mapping->nr_pages != 1); + WARN_ON_ONCE(pkvm_mapping_nr_pages(mapping) != 1); unpin_user_pages_dirty_lock(&page, 1, true); account_locked_vm(kvm->mm, 1, false); pkvm_mapping_remove(mapping, &pgt->pkvm_mappings); @@ -369,7 +392,7 @@ static int __pkvm_pgtable_stage2_unshare(struct kvm_pgtable *pgt, u64 start, u64 for_each_mapping_in_range_safe(pgt, start, end, mapping) { ret = kvm_call_hyp_nvhe(__pkvm_host_unshare_guest, handle, mapping->gfn, - mapping->nr_pages); + pkvm_mapping_nr_pages(mapping)); if (WARN_ON(ret)) return ret; pkvm_mapping_remove(mapping, &pgt->pkvm_mappings); @@ -448,7 +471,7 @@ int pkvm_pgtable_stage2_map(struct kvm_pgtable *pgt, u64 addr, u64 size, * permission faults are handled in the relax_perms() path. */ if (mapping) { - if (size == (mapping->nr_pages * PAGE_SIZE)) + if (size == (pkvm_mapping_nr_pages(mapping) * PAGE_SIZE)) return -EAGAIN; /* @@ -472,7 +495,9 @@ int pkvm_pgtable_stage2_map(struct kvm_pgtable *pgt, u64 addr, u64 size, swap(mapping, cache->mapping); mapping->gfn = gfn; mapping->pfn = pfn; - mapping->nr_pages = size / PAGE_SIZE; + pkvm_mapping_set_nr_pages(mapping, size / PAGE_SIZE, + !(prot & (KVM_PGTABLE_PROT_DEVICE | + KVM_PGTABLE_PROT_NORMAL_NC))); pkvm_mapping_insert(mapping, &pgt->pkvm_mappings); return ret; @@ -503,7 +528,7 @@ int pkvm_pgtable_stage2_wrprotect(struct kvm_pgtable *pgt, u64 addr, u64 size) lockdep_assert_held(&kvm->mmu_lock); for_each_mapping_in_range_safe(pgt, addr, addr + size, mapping) { ret = kvm_call_hyp_nvhe(__pkvm_host_wrprotect_guest, handle, mapping->gfn, - mapping->nr_pages); + pkvm_mapping_nr_pages(mapping)); if (WARN_ON(ret)) break; } @@ -517,9 +542,13 @@ int pkvm_pgtable_stage2_flush(struct kvm_pgtable *pgt, u64 addr, u64 size) struct pkvm_mapping *mapping; lockdep_assert_held(&kvm->mmu_lock); - for_each_mapping_in_range_safe(pgt, addr, addr + size, mapping) + for_each_mapping_in_range_safe(pgt, addr, addr + size, mapping) { + if (!pkvm_mapping_is_cacheable(mapping)) + continue; + __clean_dcache_guest_page(pfn_to_kaddr(mapping->pfn), - PAGE_SIZE * mapping->nr_pages); + PAGE_SIZE * pkvm_mapping_nr_pages(mapping)); + } return 0; } @@ -536,8 +565,10 @@ bool pkvm_pgtable_stage2_test_clear_young(struct kvm_pgtable *pgt, u64 addr, u64 lockdep_assert_held(&kvm->mmu_lock); for_each_mapping_in_range_safe(pgt, addr, addr + size, mapping) - young |= kvm_call_hyp_nvhe(__pkvm_host_test_clear_young_guest, handle, mapping->gfn, - mapping->nr_pages, mkold); + young |= kvm_call_hyp_nvhe(__pkvm_host_test_clear_young_guest, + handle, mapping->gfn, + pkvm_mapping_nr_pages(mapping), + mkold); return young; } -- 2.53.0