From patchwork Wed Apr 19 12:20:51 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Will Deacon X-Patchwork-Id: 13216758 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 ADA98C77B7E for ; Wed, 19 Apr 2023 12:22:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=lW0Yg5G68s+pKiOeezzN6dU29U0m7ACZtVf7uywqiFY=; b=FBIuwFPbVUQPWr JaefRts0JfR5j4GgLShh+tnAhvwPP6B2IeslrbehVkZI5/ReUKrHYviw8FaOHO9stk+FJ8IW1bmuU CX2CrH89jJRu0+bSWIXsVZqRDZAwnmUwLSh1HEdGRVblhrPE9wIxipeH02JeiZEYf65ol6K9ZqEJl eMmMVef3OxaANcq0V+M50ieukz93FeWHUXur29xZOO9KUGXeBzXhy5FpEXfLug4AN7SUBunr8phDx QLxki/9GjXt+VbQZpHQPrMbOH71WpacS7ckFu3vMlAyySXzhjuJv508tFs+fjpogr9q41H25Bl/Z9 mfSBvEbjF70KKLkGWROQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1pp6ok-005KpW-2x; Wed, 19 Apr 2023 12:21:46 +0000 Received: from dfw.source.kernel.org ([2604:1380:4641:c500::1]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1pp6oS-005KeN-1g for linux-arm-kernel@lists.infradead.org; Wed, 19 Apr 2023 12:21:31 +0000 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id EDBCC631D4; Wed, 19 Apr 2023 12:21:27 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A90F7C4339B; Wed, 19 Apr 2023 12:21:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1681906887; bh=SmUqVjCAaBqnXVoiv057Ynztj5828L9ALAY2C+PHOuQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=nmAvWu5Cw9C0UkkjnoLaf6FZ1/OAaQeDNq7aG36sCIA5OwluK4nrp4Xl7RpuWKQc+ jHBcNmNFHyKt6ZkR698tquEU9B3/GaFz2OnwIkHKnAezrs+HQOeoqzzlW4m4E8OSS2 hDp6SPKZJ3IiV+GhivF+izlSCkls+RLSjywGXm+6Z/lF7UmoceHKvbjpQ1q/EvneY5 ehovWZVJexUVeaXmLmq9H/+clvnZc4+5mekqk7fpiaS0wCBARhLyqPDzm43RRvDeEV L1AD/+Xp09zZsmQYhTekx8CAaK6Zhu4sOmx1KanCrdTzSz4NKtBcC4KiiaHVx8z67n CnQyAKv7xsFmA== From: Will Deacon To: linux-arm-kernel@lists.infradead.org Cc: Will Deacon , Quentin Perret , Marc Zyngier , Oliver Upton , James Morse , Alexandru Elisei , Suzuki K Poulose , Sudeep Holla , Sebastian Ene , Fuad Tabba , kvmarm@lists.linux.dev, kernel-team@android.com, Andrew Walbran Subject: [PATCH v2 10/10] KVM: arm64: pkvm: Add support for fragmented FF-A descriptors Date: Wed, 19 Apr 2023 13:20:51 +0100 Message-Id: <20230419122051.1341-11-will@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20230419122051.1341-1-will@kernel.org> References: <20230419122051.1341-1-will@kernel.org> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230419_052128_655070_E41E17FD X-CRM114-Status: GOOD ( 30.10 ) 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 From: Quentin Perret FF-A memory descriptors may need to be sent in fragments when they don't fit in the mailboxes. Doing so involves using the FRAG_TX and FRAG_RX primitives defined in the FF-A protocol. Add support in the pKVM FF-A relayer for fragmented descriptors by monitoring outgoing FRAG_TX transactions and by buffering large descriptors on the reclaim path. Co-developed-by: Andrew Walbran Signed-off-by: Andrew Walbran Signed-off-by: Quentin Perret Signed-off-by: Will Deacon --- arch/arm64/include/asm/kvm_pkvm.h | 17 ++- arch/arm64/kvm/hyp/nvhe/ffa.c | 170 ++++++++++++++++++++++++++---- 2 files changed, 162 insertions(+), 25 deletions(-) diff --git a/arch/arm64/include/asm/kvm_pkvm.h b/arch/arm64/include/asm/kvm_pkvm.h index 2b495ec59deb..e46250a02017 100644 --- a/arch/arm64/include/asm/kvm_pkvm.h +++ b/arch/arm64/include/asm/kvm_pkvm.h @@ -6,7 +6,9 @@ #ifndef __ARM64_KVM_PKVM_H__ #define __ARM64_KVM_PKVM_H__ +#include #include +#include #include /* Maximum number of VMs that can co-exist under pKVM. */ @@ -110,8 +112,19 @@ static inline unsigned long host_s2_pgtable_pages(void) static inline unsigned long hyp_ffa_proxy_pages(void) { - /* A page each for the hypervisor's RX and TX mailboxes. */ - return 2 * KVM_FFA_MBOX_NR_PAGES; + size_t desc_max; + + /* + * The hypervisor FFA proxy needs enough memory to buffer a fragmented + * descriptor returned from EL3 in response to a RETRIEVE_REQ call. + */ + desc_max = sizeof(struct ffa_mem_region) + + sizeof(struct ffa_mem_region_attributes) + + sizeof(struct ffa_composite_mem_region) + + SG_MAX_SEGMENTS * sizeof(struct ffa_mem_region_addr_range); + + /* Plus a page each for the hypervisor's RX and TX mailboxes. */ + return (2 * KVM_FFA_MBOX_NR_PAGES) + DIV_ROUND_UP(desc_max, PAGE_SIZE); } #endif /* __ARM64_KVM_PKVM_H__ */ diff --git a/arch/arm64/kvm/hyp/nvhe/ffa.c b/arch/arm64/kvm/hyp/nvhe/ffa.c index aa8bfc97a164..a787f9134c39 100644 --- a/arch/arm64/kvm/hyp/nvhe/ffa.c +++ b/arch/arm64/kvm/hyp/nvhe/ffa.c @@ -42,6 +42,18 @@ */ #define HOST_FFA_ID 0 +/* + * A buffer to hold the maximum descriptor size we can see from the host, + * which is required when the SPMD returns a fragmented FFA_MEM_RETRIEVE_RESP + * when resolving the handle on the reclaim path. + */ +struct kvm_ffa_descriptor_buffer { + void *buf; + size_t len; +}; + +static struct kvm_ffa_descriptor_buffer ffa_desc_buf; + struct kvm_ffa_buffers { hyp_spinlock_t lock; void *tx; @@ -122,6 +134,24 @@ static int spmd_unmap_ffa_buffers(void) return res.a0 == FFA_SUCCESS ? FFA_RET_SUCCESS : res.a2; } +static void spmd_mem_frag_tx(struct arm_smccc_res *res, u32 handle_lo, + u32 handle_hi, u32 fraglen, u32 endpoint_id) +{ + arm_smccc_1_1_smc(FFA_MEM_FRAG_TX, + handle_lo, handle_hi, fraglen, endpoint_id, + 0, 0, 0, + res); +} + +static void spmd_mem_frag_rx(struct arm_smccc_res *res, u32 handle_lo, + u32 handle_hi, u32 fragoff) +{ + arm_smccc_1_1_smc(FFA_MEM_FRAG_RX, + handle_lo, handle_hi, fragoff, HOST_FFA_ID, + 0, 0, 0, + res); +} + static void spmd_mem_xfer(struct arm_smccc_res *res, u64 func_id, u32 len, u32 fraglen) { @@ -323,6 +353,64 @@ static int ffa_host_unshare_ranges(struct ffa_mem_region_addr_range *ranges, return ret; } +static void do_ffa_mem_frag_tx(struct arm_smccc_res *res, + struct kvm_cpu_context *ctxt) +{ + DECLARE_REG(u32, handle_lo, ctxt, 1); + DECLARE_REG(u32, handle_hi, ctxt, 2); + DECLARE_REG(u32, fraglen, ctxt, 3); + DECLARE_REG(u32, endpoint_id, ctxt, 4); + struct ffa_mem_region_addr_range *buf; + int ret = FFA_RET_INVALID_PARAMETERS; + u32 nr_ranges; + + if (fraglen > KVM_FFA_MBOX_NR_PAGES * PAGE_SIZE) + goto out; + + if (fraglen % sizeof(*buf)) + goto out; + + hyp_spin_lock(&host_buffers.lock); + if (!host_buffers.tx) + goto out_unlock; + + buf = hyp_buffers.tx; + memcpy(buf, host_buffers.tx, fraglen); + nr_ranges = fraglen / sizeof(*buf); + + ret = ffa_host_share_ranges(buf, nr_ranges); + if (ret) { + /* + * We're effectively aborting the transaction, so we need + * to restore the global state back to what it was prior to + * transmission of the first fragment. + */ + spmd_mem_reclaim(res, handle_lo, handle_hi, 0); + WARN_ON(res->a0 != FFA_SUCCESS); + goto out_unlock; + } + + spmd_mem_frag_tx(res, handle_lo, handle_hi, fraglen, endpoint_id); + if (res->a0 != FFA_SUCCESS && res->a0 != FFA_MEM_FRAG_RX) + WARN_ON(ffa_host_unshare_ranges(buf, nr_ranges)); + +out_unlock: + hyp_spin_unlock(&host_buffers.lock); +out: + if (ret) + ffa_to_smccc_res(res, ret); + + /* + * If for any reason this did not succeed, we're in trouble as we have + * now lost the content of the previous fragments and we can't rollback + * the host stage-2 changes. The pages previously marked as shared will + * remain stuck in that state forever, hence preventing the host from + * sharing/donating them again and may possibly lead to subsequent + * failures, but this will not compromise confidentiality. + */ + return; +} + static __always_inline void do_ffa_mem_xfer(const u64 func_id, struct arm_smccc_res *res, struct kvm_cpu_context *ctxt) @@ -333,8 +421,8 @@ static __always_inline void do_ffa_mem_xfer(const u64 func_id, DECLARE_REG(u32, npages_mbz, ctxt, 4); struct ffa_composite_mem_region *reg; struct ffa_mem_region *buf; + u32 offset, nr_ranges; int ret = 0; - u32 offset; BUILD_BUG_ON(func_id != FFA_FN64_MEM_SHARE && func_id != FFA_FN64_MEM_LEND); @@ -345,11 +433,6 @@ static __always_inline void do_ffa_mem_xfer(const u64 func_id, goto out; } - if (fraglen < len) { - ret = FFA_RET_ABORTED; - goto out; - } - if (fraglen < sizeof(struct ffa_mem_region) + sizeof(struct ffa_mem_region_attributes)) { ret = FFA_RET_INVALID_PARAMETERS; @@ -377,21 +460,26 @@ static __always_inline void do_ffa_mem_xfer(const u64 func_id, } reg = (void *)buf + offset; - if (fraglen < offset + sizeof(struct ffa_composite_mem_region) + - reg->addr_range_cnt * - sizeof(struct ffa_mem_region_addr_range)) { + nr_ranges = ((void *)buf + fraglen) - (void *)reg->constituents; + if (nr_ranges % sizeof(reg->constituents[0])) { ret = FFA_RET_INVALID_PARAMETERS; goto out_unlock; } - ret = ffa_host_share_ranges(reg->constituents, reg->addr_range_cnt); + nr_ranges /= sizeof(reg->constituents[0]); + ret = ffa_host_share_ranges(reg->constituents, nr_ranges); if (ret) goto out_unlock; spmd_mem_xfer(res, func_id, len, fraglen); - if (res->a0 != FFA_SUCCESS) { - WARN_ON(ffa_host_unshare_ranges(reg->constituents, - reg->addr_range_cnt)); + if (fraglen != len) { + if (res->a0 != FFA_MEM_FRAG_RX) + goto err_unshare; + + if (res->a3 != fraglen) + goto err_unshare; + } else if (res->a0 != FFA_SUCCESS) { + goto err_unshare; } out_unlock: @@ -400,6 +488,10 @@ static __always_inline void do_ffa_mem_xfer(const u64 func_id, if (ret) ffa_to_smccc_res(res, ret); return; + +err_unshare: + WARN_ON(ffa_host_unshare_ranges(reg->constituents, nr_ranges)); + goto out_unlock; } static void do_ffa_mem_reclaim(struct arm_smccc_res *res, @@ -409,9 +501,9 @@ static void do_ffa_mem_reclaim(struct arm_smccc_res *res, DECLARE_REG(u32, handle_hi, ctxt, 2); DECLARE_REG(u32, flags, ctxt, 3); struct ffa_composite_mem_region *reg; + u32 offset, len, fraglen, fragoff; struct ffa_mem_region *buf; int ret = 0; - u32 offset; u64 handle; handle = PACK_HANDLE(handle_lo, handle_hi); @@ -429,11 +521,8 @@ static void do_ffa_mem_reclaim(struct arm_smccc_res *res, if (res->a0 != FFA_MEM_RETRIEVE_RESP) goto out_unlock; - /* Check for fragmentation */ - if (res->a1 != res->a2) { - ret = FFA_RET_ABORTED; - goto out_unlock; - } + len = res->a1; + fraglen = res->a2; offset = buf->ep_mem_access[0].composite_off; /* @@ -441,16 +530,36 @@ static void do_ffa_mem_reclaim(struct arm_smccc_res *res, * check that we end up with something that doesn't look _completely_ * bogus. */ - if (WARN_ON(offset > KVM_FFA_MBOX_NR_PAGES * PAGE_SIZE)) { + if (WARN_ON(offset > len || + fraglen > KVM_FFA_MBOX_NR_PAGES * PAGE_SIZE)) { ret = FFA_RET_ABORTED; goto out_unlock; } - reg = (void *)buf + offset; + if (len > ffa_desc_buf.len) { + ret = FFA_RET_NO_MEMORY; + goto out_unlock; + } + + buf = ffa_desc_buf.buf; + memcpy(buf, hyp_buffers.rx, fraglen); + + for (fragoff = fraglen; fragoff < len; fragoff += fraglen) { + spmd_mem_frag_rx(res, handle_lo, handle_hi, fragoff); + if (res->a0 != FFA_MEM_FRAG_TX) { + ret = FFA_RET_INVALID_PARAMETERS; + goto out_unlock; + } + + fraglen = res->a3; + memcpy((void *)buf + fragoff, hyp_buffers.rx, fraglen); + } + spmd_mem_reclaim(res, handle_lo, handle_hi, flags); if (res->a0 != FFA_SUCCESS) goto out_unlock; + reg = (void *)buf + offset; /* If the SPMD was happy, then we should be too. */ WARN_ON(ffa_host_unshare_ranges(reg->constituents, reg->addr_range_cnt)); @@ -552,6 +661,9 @@ bool kvm_host_ffa_handler(struct kvm_cpu_context *host_ctxt) case FFA_FN64_MEM_LEND: do_ffa_mem_xfer(FFA_FN64_MEM_LEND, &res, host_ctxt); goto out_handled; + case FFA_MEM_FRAG_TX: + do_ffa_mem_frag_tx(&res, host_ctxt); + goto out_handled; } if (ffa_call_supported(func_id)) @@ -567,6 +679,7 @@ int hyp_ffa_init(void *pages) { struct arm_smccc_res res; size_t min_rxtx_sz; + void *tx, *rx; if (kvm_host_psci_config.smccc_version < ARM_SMCCC_VERSION_1_2) return 0; @@ -607,10 +720,21 @@ int hyp_ffa_init(void *pages) if (min_rxtx_sz > PAGE_SIZE) return -EOPNOTSUPP; + tx = pages; + pages += KVM_FFA_MBOX_NR_PAGES * PAGE_SIZE; + rx = pages; + pages += KVM_FFA_MBOX_NR_PAGES * PAGE_SIZE; + + ffa_desc_buf = (struct kvm_ffa_descriptor_buffer) { + .buf = pages, + .len = PAGE_SIZE * + (hyp_ffa_proxy_pages() - (2 * KVM_FFA_MBOX_NR_PAGES)), + }; + hyp_buffers = (struct kvm_ffa_buffers) { .lock = __HYP_SPIN_LOCK_UNLOCKED, - .tx = pages, - .rx = pages + (KVM_FFA_MBOX_NR_PAGES * PAGE_SIZE), + .tx = tx, + .rx = rx, }; host_buffers = (struct kvm_ffa_buffers) {