From patchwork Fri Oct 7 23:41:51 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Oliver Upton X-Patchwork-Id: 13001551 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9514FC433F5 for ; Fri, 7 Oct 2022 23:43:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229579AbiJGXnh (ORCPT ); Fri, 7 Oct 2022 19:43:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34634 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229791AbiJGXmK (ORCPT ); Fri, 7 Oct 2022 19:42:10 -0400 Received: from out2.migadu.com (out2.migadu.com [188.165.223.204]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 635A7A98F7 for ; Fri, 7 Oct 2022 16:42:09 -0700 (PDT) X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1665186128; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=jNR9v+pyT8sFr1ZTIk/kdWwXQQaalAe+phJ9dBDtUZ8=; b=pbis3U7feRQowbfrXDCwsu5OCSHoDfMs4pUYh/XGf6iyQUkA0UV8liUKktITLkUG857H2k xhRuHPZCA0yI8RPpBiMn01BmpD6qqHZaQli9sss4UVuiMfa656OfLrP7FpLbzrY2XvZaFF cjppQjXwrMX6qBA0c79pb4YiBrQko04= From: Oliver Upton To: Marc Zyngier , James Morse , Alexandru Elisei Cc: linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, Ricardo Koller , David Matlack , Quentin Perret , kvmarm@lists.linux.dev, Oliver Upton Subject: [PATCH v3 2/2] KVM: arm64: Limit stage2_apply_range() batch size to largest block Date: Fri, 7 Oct 2022 23:41:51 +0000 Message-Id: <20221007234151.461779-3-oliver.upton@linux.dev> In-Reply-To: <20221007234151.461779-1-oliver.upton@linux.dev> References: <20221007234151.461779-1-oliver.upton@linux.dev> MIME-Version: 1.0 X-Migadu-Flow: FLOW_OUT Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Presently stage2_apply_range() works on a batch of memory addressed by a stage 2 root table entry for the VM. Depending on the IPA limit of the VM and PAGE_SIZE of the host, this could address a massive range of memory. Some examples: 4 level, 4K paging -> 512 GB batch size 3 level, 64K paging -> 4TB batch size Unsurprisingly, working on such a large range of memory can lead to soft lockups. When running dirty_log_perf_test: ./dirty_log_perf_test -m -2 -s anonymous_thp -b 4G -v 48 watchdog: BUG: soft lockup - CPU#0 stuck for 45s! [dirty_log_perf_:16703] Modules linked in: vfat fat cdc_ether usbnet mii xhci_pci xhci_hcd sha3_generic gq(O) CPU: 0 PID: 16703 Comm: dirty_log_perf_ Tainted: G O 6.0.0-smp-DEV #1 pstate: 80400009 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : dcache_clean_inval_poc+0x24/0x38 lr : clean_dcache_guest_page+0x28/0x4c sp : ffff800021763990 pmr_save: 000000e0 x29: ffff800021763990 x28: 0000000000000005 x27: 0000000000000de0 x26: 0000000000000001 x25: 00400830b13bc77f x24: ffffad4f91ead9c0 x23: 0000000000000000 x22: ffff8000082ad9c8 x21: 0000fffafa7bc000 x20: ffffad4f9066ce50 x19: 0000000000000003 x18: ffffad4f92402000 x17: 000000000000011b x16: 000000000000011b x15: 0000000000000124 x14: ffff07ff8301d280 x13: 0000000000000000 x12: 00000000ffffffff x11: 0000000000010001 x10: fffffc0000000000 x9 : ffffad4f9069e580 x8 : 000000000000000c x7 : 0000000000000000 x6 : 000000000000003f x5 : ffff07ffa2076980 x4 : 0000000000000001 x3 : 000000000000003f x2 : 0000000000000040 x1 : ffff0830313bd000 x0 : ffff0830313bcc40 Call trace: dcache_clean_inval_poc+0x24/0x38 stage2_unmap_walker+0x138/0x1ec __kvm_pgtable_walk+0x130/0x1d4 __kvm_pgtable_walk+0x170/0x1d4 __kvm_pgtable_walk+0x170/0x1d4 __kvm_pgtable_walk+0x170/0x1d4 kvm_pgtable_stage2_unmap+0xc4/0xf8 kvm_arch_flush_shadow_memslot+0xa4/0x10c kvm_set_memslot+0xb8/0x454 __kvm_set_memory_region+0x194/0x244 kvm_vm_ioctl_set_memory_region+0x58/0x7c kvm_vm_ioctl+0x49c/0x560 __arm64_sys_ioctl+0x9c/0xd4 invoke_syscall+0x4c/0x124 el0_svc_common+0xc8/0x194 do_el0_svc+0x38/0xc0 el0_svc+0x2c/0xa4 el0t_64_sync_handler+0x84/0xf0 el0t_64_sync+0x1a0/0x1a4 Use the largest supported block mapping for the configured page size as the batch granularity. In so doing the walker is guaranteed to visit a leaf only once. Signed-off-by: Oliver Upton --- arch/arm64/include/asm/stage2_pgtable.h | 20 -------------------- arch/arm64/kvm/mmu.c | 9 ++++++++- 2 files changed, 8 insertions(+), 21 deletions(-) diff --git a/arch/arm64/include/asm/stage2_pgtable.h b/arch/arm64/include/asm/stage2_pgtable.h index fe341a6578c3..c8dca8ae359c 100644 --- a/arch/arm64/include/asm/stage2_pgtable.h +++ b/arch/arm64/include/asm/stage2_pgtable.h @@ -10,13 +10,6 @@ #include -/* - * PGDIR_SHIFT determines the size a top-level page table entry can map - * and depends on the number of levels in the page table. Compute the - * PGDIR_SHIFT for a given number of levels. - */ -#define pt_levels_pgdir_shift(lvls) ARM64_HW_PGTABLE_LEVEL_SHIFT(4 - (lvls)) - /* * The hardware supports concatenation of up to 16 tables at stage2 entry * level and we use the feature whenever possible, which means we resolve 4 @@ -30,11 +23,6 @@ #define stage2_pgtable_levels(ipa) ARM64_HW_PGTABLE_LEVELS((ipa) - 4) #define kvm_stage2_levels(kvm) VTCR_EL2_LVLS(kvm->arch.vtcr) -/* stage2_pgdir_shift() is the size mapped by top-level stage2 entry for the VM */ -#define stage2_pgdir_shift(kvm) pt_levels_pgdir_shift(kvm_stage2_levels(kvm)) -#define stage2_pgdir_size(kvm) (1ULL << stage2_pgdir_shift(kvm)) -#define stage2_pgdir_mask(kvm) ~(stage2_pgdir_size(kvm) - 1) - /* * kvm_mmmu_cache_min_pages() is the number of pages required to install * a stage-2 translation. We pre-allocate the entry level page table at @@ -42,12 +30,4 @@ */ #define kvm_mmu_cache_min_pages(kvm) (kvm_stage2_levels(kvm) - 1) -static inline phys_addr_t -stage2_pgd_addr_end(struct kvm *kvm, phys_addr_t addr, phys_addr_t end) -{ - phys_addr_t boundary = (addr + stage2_pgdir_size(kvm)) & stage2_pgdir_mask(kvm); - - return (boundary - 1 < end - 1) ? boundary : end; -} - #endif /* __ARM64_S2_PGTABLE_H_ */ diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index c9a13e487187..caf6cfeff35b 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -31,6 +31,13 @@ static phys_addr_t hyp_idmap_vector; static unsigned long io_map_base; +static phys_addr_t stage2_range_addr_end(phys_addr_t addr, phys_addr_t end) +{ + phys_addr_t size = kvm_granule_size(KVM_PGTABLE_MIN_BLOCK_LEVEL); + phys_addr_t boundary = ALIGN_DOWN(addr + size, size); + + return (boundary - 1 < end - 1) ? boundary : end; +} /* * Release kvm_mmu_lock periodically if the memory region is large. Otherwise, @@ -52,7 +59,7 @@ static int stage2_apply_range(struct kvm *kvm, phys_addr_t addr, if (!pgt) return -EINVAL; - next = stage2_pgd_addr_end(kvm, addr, end); + next = stage2_range_addr_end(addr, end); ret = fn(pgt, addr, next - addr); if (ret) break;