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a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-transfer-encoding :content-language; bh=eSrfHixI8CRkmO34CVpc+ZRZhqn7TykEpy53kp85QiA=; b=tPdbO140e9H1ZykBSdOS1sQFcQliw1yX7WsoNtW5P8mE58BkjN0MQmegfcT7QoYkL0 dlRwtMWcqt63XC1BLm8mbpOWTjmD4skQO1M91lxWxOeDMhnTfllZXb45kSJk1/nz/LPV DuqnT7v5/+LCncc5c3SL+fvSjkeIm4qSq4Su+YGIVKN0bI7dRftwzLSG/CCvw2UhQkgt MI9JgZVHF6yyfTjLchUMzRWn30vB8zSP5UdyOIED6N0vswokzK9lpLptaRlrw+YVcPpy bNMpsDzFTfgFdJsCrGgSOQeMActsaJUOq0xCPSF4Vz2dqkeVzqpfYL73jnre+7hjRlVq de4w== X-Gm-Message-State: AOAM532WqNEdSX5myR5hooVsQc7OWgBPMPtGpTwlnpD941l1PNq/2pD2 f0/grLCakIBxjPUdQunyp80= X-Google-Smtp-Source: ABdhPJwOGO2pFef1l1LzMAhYURGFX6N0dKB995JVawqAKJ/up+SBjA54KSr/99C0K4P6g1kC8lNIfg== X-Received: by 2002:ac2:4ec1:: with SMTP id p1mr1707877lfr.394.1607554185331; Wed, 09 Dec 2020 14:49:45 -0800 (PST) Subject: Re: [PATCH V3 14/23] arm/ioreq: Introduce arch specific bits for IOREQ/DM features To: Stefano Stabellini Cc: xen-devel@lists.xenproject.org, Julien Grall , Julien Grall , Volodymyr Babchuk , Oleksandr Tyshchenko References: <1606732298-22107-1-git-send-email-olekstysh@gmail.com> <1606732298-22107-15-git-send-email-olekstysh@gmail.com> From: Oleksandr Message-ID: <31e35f5d-5ab4-19bf-e36b-8e7c0b7bf7d4@gmail.com> Date: Thu, 10 Dec 2020 00:49:44 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US On 10.12.20 00:04, Stefano Stabellini wrote: Hi Stefano > On Mon, 30 Nov 2020, Oleksandr Tyshchenko wrote: >> From: Julien Grall >> >> This patch adds basic IOREQ/DM support on Arm. The subsequent >> patches will improve functionality and add remaining bits. >> >> The IOREQ/DM features are supposed to be built with IOREQ_SERVER >> option enabled, which is disabled by default on Arm for now. >> >> Please note, the "PIO handling" TODO is expected to left unaddressed >> for the current series. It is not an big issue for now while Xen >> doesn't have support for vPCI on Arm. On Arm64 they are only used >> for PCI IO Bar and we would probably want to expose them to emulator >> as PIO access to make a DM completely arch-agnostic. So "PIO handling" >> should be implemented when we add support for vPCI. >> >> Signed-off-by: Julien Grall >> Signed-off-by: Oleksandr Tyshchenko >> >> --- >> Please note, this is a split/cleanup/hardening of Julien's PoC: >> "Add support for Guest IO forwarding to a device emulator" >> >> Changes RFC -> V1: >> - was split into: >> - arm/ioreq: Introduce arch specific bits for IOREQ/DM features >> - xen/mm: Handle properly reference in set_foreign_p2m_entry() on Arm >> - update patch description >> - update asm-arm/hvm/ioreq.h according to the newly introduced arch functions: >> - arch_hvm_destroy_ioreq_server() >> - arch_handle_hvm_io_completion() >> - update arch files to include xen/ioreq.h >> - remove HVMOP plumbing >> - rewrite a logic to handle properly case when hvm_send_ioreq() returns IO_RETRY >> - add a logic to handle properly handle_hvm_io_completion() return value >> - rename handle_mmio() to ioreq_handle_complete_mmio() >> - move paging_mark_pfn_dirty() to asm-arm/paging.h >> - remove forward declaration for hvm_ioreq_server in asm-arm/paging.h >> - move try_fwd_ioserv() to ioreq.c, provide stubs if !CONFIG_IOREQ_SERVER >> - do not remove #ifdef CONFIG_IOREQ_SERVER in memory.c for guarding xen/ioreq.h >> - use gdprintk in try_fwd_ioserv(), remove unneeded prints >> - update list of #include-s >> - move has_vpci() to asm-arm/domain.h >> - add a comment (TODO) to unimplemented yet handle_pio() >> - remove hvm_mmio_first(last)_byte() and hvm_ioreq_(page/vcpu/server) structs >> from the arch files, they were already moved to the common code >> - remove set_foreign_p2m_entry() changes, they will be properly implemented >> in the follow-up patch >> - select IOREQ_SERVER for Arm instead of Arm64 in Kconfig >> - remove x86's realmode and other unneeded stubs from xen/ioreq.h >> - clafify ioreq_t p.df usage in try_fwd_ioserv() >> - set ioreq_t p.count to 1 in try_fwd_ioserv() >> >> Changes V1 -> V2: >> - was split into: >> - arm/ioreq: Introduce arch specific bits for IOREQ/DM features >> - xen/arm: Stick around in leave_hypervisor_to_guest until I/O has completed >> - update the author of a patch >> - update patch description >> - move a loop in leave_hypervisor_to_guest() to a separate patch >> - set IOREQ_SERVER disabled by default >> - remove already clarified /* XXX */ >> - replace BUG() by ASSERT_UNREACHABLE() in handle_pio() >> - remove default case for handling the return value of try_handle_mmio() >> - remove struct hvm_domain, enum hvm_io_completion, struct hvm_vcpu_io, >> struct hvm_vcpu from asm-arm/domain.h, these are common materials now >> - update everything according to the recent changes (IOREQ related function >> names don't contain "hvm" prefixes/infixes anymore, IOREQ related fields >> are part of common struct vcpu/domain now, etc) >> >> Changes V2 -> V3: >> - update patch according the "legacy interface" is x86 specific >> - add dummy arch hooks >> - remove dummy paging_mark_pfn_dirty() >> - don’t include in common ioreq.c >> - don’t include in arch ioreq.h >> - remove #define ioreq_params(d, i) >> --- >> --- >> xen/arch/arm/Makefile | 2 + >> xen/arch/arm/dm.c | 34 ++++++++++ >> xen/arch/arm/domain.c | 9 +++ >> xen/arch/arm/io.c | 11 +++- >> xen/arch/arm/ioreq.c | 141 ++++++++++++++++++++++++++++++++++++++++ >> xen/arch/arm/traps.c | 13 ++++ >> xen/include/asm-arm/domain.h | 3 + >> xen/include/asm-arm/hvm/ioreq.h | 139 +++++++++++++++++++++++++++++++++++++++ >> xen/include/asm-arm/mmio.h | 1 + >> 9 files changed, 352 insertions(+), 1 deletion(-) >> create mode 100644 xen/arch/arm/dm.c >> create mode 100644 xen/arch/arm/ioreq.c >> create mode 100644 xen/include/asm-arm/hvm/ioreq.h >> >> diff --git a/xen/arch/arm/Makefile b/xen/arch/arm/Makefile >> index 296c5e6..c3ff454 100644 >> --- a/xen/arch/arm/Makefile >> +++ b/xen/arch/arm/Makefile >> @@ -13,6 +13,7 @@ obj-y += cpuerrata.o >> obj-y += cpufeature.o >> obj-y += decode.o >> obj-y += device.o >> +obj-$(CONFIG_IOREQ_SERVER) += dm.o >> obj-y += domain.o >> obj-y += domain_build.init.o >> obj-y += domctl.o >> @@ -27,6 +28,7 @@ obj-y += guest_atomics.o >> obj-y += guest_walk.o >> obj-y += hvm.o >> obj-y += io.o >> +obj-$(CONFIG_IOREQ_SERVER) += ioreq.o >> obj-y += irq.o >> obj-y += kernel.init.o >> obj-$(CONFIG_LIVEPATCH) += livepatch.o >> diff --git a/xen/arch/arm/dm.c b/xen/arch/arm/dm.c >> new file mode 100644 >> index 0000000..5d3da37 >> --- /dev/null >> +++ b/xen/arch/arm/dm.c >> @@ -0,0 +1,34 @@ >> +/* >> + * Copyright (c) 2019 Arm ltd. >> + * >> + * This program is free software; you can redistribute it and/or modify it >> + * under the terms and conditions of the GNU General Public License, >> + * version 2, as published by the Free Software Foundation. >> + * >> + * This program is distributed in the hope it will be useful, but WITHOUT >> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or >> + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for >> + * more details. >> + * >> + * You should have received a copy of the GNU General Public License along with >> + * this program; If not, see . >> + */ >> + >> +#include >> +#include >> + >> +int arch_dm_op(struct xen_dm_op *op, struct domain *d, >> + const struct dmop_args *op_args, bool *const_op) >> +{ >> + return -EOPNOTSUPP; >> +} >> + >> +/* >> + * Local variables: >> + * mode: C >> + * c-file-style: "BSD" >> + * c-basic-offset: 4 >> + * tab-width: 4 >> + * indent-tabs-mode: nil >> + * End: >> + */ >> diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c >> index 18cafcd..8f55aba 100644 >> --- a/xen/arch/arm/domain.c >> +++ b/xen/arch/arm/domain.c >> @@ -15,6 +15,7 @@ >> #include >> #include >> #include >> +#include >> #include >> #include >> #include >> @@ -696,6 +697,10 @@ int arch_domain_create(struct domain *d, >> >> ASSERT(config != NULL); >> >> +#ifdef CONFIG_IOREQ_SERVER >> + ioreq_domain_init(d); >> +#endif >> + >> /* p2m_init relies on some value initialized by the IOMMU subsystem */ >> if ( (rc = iommu_domain_init(d, config->iommu_opts)) != 0 ) >> goto fail; >> @@ -1014,6 +1019,10 @@ int domain_relinquish_resources(struct domain *d) >> if (ret ) >> return ret; >> >> +#ifdef CONFIG_IOREQ_SERVER >> + ioreq_server_destroy_all(d); >> +#endif >> + >> PROGRESS(xen): >> ret = relinquish_memory(d, &d->xenpage_list); >> if ( ret ) >> diff --git a/xen/arch/arm/io.c b/xen/arch/arm/io.c >> index ae7ef96..f44cfd4 100644 >> --- a/xen/arch/arm/io.c >> +++ b/xen/arch/arm/io.c >> @@ -23,6 +23,7 @@ >> #include >> #include >> #include >> +#include >> >> #include "decode.h" >> >> @@ -123,7 +124,15 @@ enum io_state try_handle_mmio(struct cpu_user_regs *regs, >> >> handler = find_mmio_handler(v->domain, info.gpa); >> if ( !handler ) >> - return IO_UNHANDLED; >> + { >> + int rc; >> + >> + rc = try_fwd_ioserv(regs, v, &info); >> + if ( rc == IO_HANDLED ) >> + return handle_ioserv(regs, v); >> + >> + return rc; >> + } >> >> /* All the instructions used on emulated MMIO region should be valid */ >> if ( !dabt.valid ) >> diff --git a/xen/arch/arm/ioreq.c b/xen/arch/arm/ioreq.c >> new file mode 100644 >> index 0000000..f08190c >> --- /dev/null >> +++ b/xen/arch/arm/ioreq.c >> @@ -0,0 +1,141 @@ >> +/* >> + * arm/ioreq.c: hardware virtual machine I/O emulation >> + * >> + * Copyright (c) 2019 Arm ltd. >> + * >> + * This program is free software; you can redistribute it and/or modify it >> + * under the terms and conditions of the GNU General Public License, >> + * version 2, as published by the Free Software Foundation. >> + * >> + * This program is distributed in the hope it will be useful, but WITHOUT >> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or >> + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for >> + * more details. >> + * >> + * You should have received a copy of the GNU General Public License along with >> + * this program; If not, see . >> + */ >> + >> +#include >> +#include >> + >> +#include >> + >> +#include >> + >> +enum io_state handle_ioserv(struct cpu_user_regs *regs, struct vcpu *v) >> +{ >> + const union hsr hsr = { .bits = regs->hsr }; >> + const struct hsr_dabt dabt = hsr.dabt; >> + /* Code is similar to handle_read */ >> + uint8_t size = (1 << dabt.size) * 8; >> + register_t r = v->io.req.data; >> + >> + /* We are done with the IO */ >> + v->io.req.state = STATE_IOREQ_NONE; >> + >> + if ( dabt.write ) >> + return IO_HANDLED; >> + >> + /* >> + * Sign extend if required. >> + * Note that we expect the read handler to have zeroed the bits >> + * outside the requested access size. >> + */ >> + if ( dabt.sign && (r & (1UL << (size - 1))) ) >> + { >> + /* >> + * We are relying on register_t using the same as >> + * an unsigned long in order to keep the 32-bit assembly >> + * code smaller. >> + */ >> + BUILD_BUG_ON(sizeof(register_t) != sizeof(unsigned long)); >> + r |= (~0UL) << size; >> + } >> + >> + set_user_reg(regs, dabt.reg, r); > Could you introduce a set_user_reg_signextend static inline function > that can be used both here and in handle_read? Yes, already done (this was requested by Julien). Please see https://www.mail-archive.com/xen-devel@lists.xenproject.org/msg86986.html > > >> + return IO_HANDLED; >> +} >> + >> +enum io_state try_fwd_ioserv(struct cpu_user_regs *regs, >> + struct vcpu *v, mmio_info_t *info) >> +{ >> + struct vcpu_io *vio = &v->io; >> + ioreq_t p = { >> + .type = IOREQ_TYPE_COPY, >> + .addr = info->gpa, >> + .size = 1 << info->dabt.size, >> + .count = 1, >> + .dir = !info->dabt.write, >> + /* >> + * On x86, df is used by 'rep' instruction to tell the direction >> + * to iterate (forward or backward). >> + * On Arm, all the accesses to MMIO region will do a single >> + * memory access. So for now, we can safely always set to 0. >> + */ >> + .df = 0, >> + .data = get_user_reg(regs, info->dabt.reg), >> + .state = STATE_IOREQ_READY, >> + }; >> + struct ioreq_server *s = NULL; >> + enum io_state rc; >> + >> + switch ( vio->req.state ) >> + { >> + case STATE_IOREQ_NONE: >> + break; >> + >> + case STATE_IORESP_READY: >> + return IO_HANDLED; >> + >> + default: >> + gdprintk(XENLOG_ERR, "wrong state %u\n", vio->req.state); >> + return IO_ABORT; >> + } >> + >> + s = ioreq_server_select(v->domain, &p); >> + if ( !s ) >> + return IO_UNHANDLED; >> + >> + if ( !info->dabt.valid ) >> + return IO_ABORT; >> + >> + vio->req = p; >> + >> + rc = ioreq_send(s, &p, 0); >> + if ( rc != IO_RETRY || v->domain->is_shutting_down ) >> + vio->req.state = STATE_IOREQ_NONE; >> + else if ( !ioreq_needs_completion(&vio->req) ) >> + rc = IO_HANDLED; >> + else >> + vio->completion = IO_mmio_completion; >> + >> + return rc; >> +} >> + >> +bool ioreq_complete_mmio(void) >> +{ >> + struct vcpu *v = current; >> + struct cpu_user_regs *regs = guest_cpu_user_regs(); >> + const union hsr hsr = { .bits = regs->hsr }; >> + paddr_t addr = v->io.req.addr; >> + >> + if ( try_handle_mmio(regs, hsr, addr) == IO_HANDLED ) >> + { >> + advance_pc(regs, hsr); >> + return true; >> + } >> + >> + return false; >> +} >> + >> +/* >> + * Local variables: >> + * mode: C >> + * c-file-style: "BSD" >> + * c-basic-offset: 4 >> + * tab-width: 4 >> + * indent-tabs-mode: nil >> + * End: >> + */ >> diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c >> index 22bd1bd..036b13f 100644 >> --- a/xen/arch/arm/traps.c >> +++ b/xen/arch/arm/traps.c >> @@ -21,6 +21,7 @@ >> #include >> #include >> #include >> +#include >> #include >> #include >> #include >> @@ -1385,6 +1386,9 @@ static arm_hypercall_t arm_hypercall_table[] = { >> #ifdef CONFIG_HYPFS >> HYPERCALL(hypfs_op, 5), >> #endif >> +#ifdef CONFIG_IOREQ_SERVER >> + HYPERCALL(dm_op, 3), >> +#endif >> }; >> >> #ifndef NDEBUG >> @@ -1956,6 +1960,9 @@ static void do_trap_stage2_abort_guest(struct cpu_user_regs *regs, >> case IO_HANDLED: >> advance_pc(regs, hsr); >> return; >> + case IO_RETRY: >> + /* finish later */ >> + return; >> case IO_UNHANDLED: >> /* IO unhandled, try another way to handle it. */ >> break; >> @@ -2254,6 +2261,12 @@ static void check_for_vcpu_work(void) >> { >> struct vcpu *v = current; >> >> +#ifdef CONFIG_IOREQ_SERVER >> + local_irq_enable(); >> + vcpu_ioreq_handle_completion(v); >> + local_irq_disable(); >> +#endif >> + >> if ( likely(!v->arch.need_flush_to_ram) ) >> return; >> >> diff --git a/xen/include/asm-arm/domain.h b/xen/include/asm-arm/domain.h >> index 6819a3b..c235e5b 100644 >> --- a/xen/include/asm-arm/domain.h >> +++ b/xen/include/asm-arm/domain.h >> @@ -10,6 +10,7 @@ >> #include >> #include >> #include >> +#include >> #include >> >> struct hvm_domain >> @@ -262,6 +263,8 @@ static inline void arch_vcpu_block(struct vcpu *v) {} >> >> #define arch_vm_assist_valid_mask(d) (1UL << VMASST_TYPE_runstate_update_flag) >> >> +#define has_vpci(d) ({ (void)(d); false; }) >> + >> #endif /* __ASM_DOMAIN_H__ */ >> >> /* >> diff --git a/xen/include/asm-arm/hvm/ioreq.h b/xen/include/asm-arm/hvm/ioreq.h >> new file mode 100644 >> index 0000000..2bffc7a >> --- /dev/null >> +++ b/xen/include/asm-arm/hvm/ioreq.h >> @@ -0,0 +1,139 @@ >> +/* >> + * hvm.h: Hardware virtual machine assist interface definitions. >> + * >> + * Copyright (c) 2016 Citrix Systems Inc. >> + * Copyright (c) 2019 Arm ltd. >> + * >> + * This program is free software; you can redistribute it and/or modify it >> + * under the terms and conditions of the GNU General Public License, >> + * version 2, as published by the Free Software Foundation. >> + * >> + * This program is distributed in the hope it will be useful, but WITHOUT >> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or >> + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for >> + * more details. >> + * >> + * You should have received a copy of the GNU General Public License along with >> + * this program; If not, see . >> + */ >> + >> +#ifndef __ASM_ARM_HVM_IOREQ_H__ >> +#define __ASM_ARM_HVM_IOREQ_H__ >> + >> +#include >> + >> +#ifdef CONFIG_IOREQ_SERVER >> +enum io_state handle_ioserv(struct cpu_user_regs *regs, struct vcpu *v); >> +enum io_state try_fwd_ioserv(struct cpu_user_regs *regs, >> + struct vcpu *v, mmio_info_t *info); >> +#else >> +static inline enum io_state handle_ioserv(struct cpu_user_regs *regs, >> + struct vcpu *v) >> +{ >> + return IO_UNHANDLED; >> +} >> + >> +static inline enum io_state try_fwd_ioserv(struct cpu_user_regs *regs, >> + struct vcpu *v, mmio_info_t *info) >> +{ >> + return IO_UNHANDLED; >> +} >> +#endif > If we are providing stub functions, then we can also provide stub > functions for: > > ioreq_domain_init > ioreq_server_destroy_all > > and avoid the ifdefs. I got your point. These are common IOREQ interface functions, which declarations live in the common header, should I provide stubs in the common ioreq.h? > > >> +bool ioreq_complete_mmio(void); >> + >> +static inline bool handle_pio(uint16_t port, unsigned int size, int dir) >> +{ >> + /* >> + * TODO: For Arm64, the main user will be PCI. So this should be >> + * implemented when we add support for vPCI. >> + */ >> + ASSERT_UNREACHABLE(); >> + return true; >> +} >> + >> +static inline void msix_write_completion(struct vcpu *v) >> +{ >> +} >> + >> +static inline bool arch_vcpu_ioreq_completion(enum io_completion io_completion) >> +{ >> + ASSERT_UNREACHABLE(); >> + return true; >> +} >> + >> +/* >> + * The "legacy" mechanism of mapping magic pages for the IOREQ servers >> + * is x86 specific, so the following hooks don't need to be implemented on Arm: >> + * - arch_ioreq_server_map_pages >> + * - arch_ioreq_server_unmap_pages >> + * - arch_ioreq_server_enable >> + * - arch_ioreq_server_disable >> + */ >> +static inline int arch_ioreq_server_map_pages(struct ioreq_server *s) >> +{ >> + return -EOPNOTSUPP; >> +} >> + >> +static inline void arch_ioreq_server_unmap_pages(struct ioreq_server *s) >> +{ >> +} >> + >> +static inline void arch_ioreq_server_enable(struct ioreq_server *s) >> +{ >> +} >> + >> +static inline void arch_ioreq_server_disable(struct ioreq_server *s) >> +{ >> +} >> + >> +static inline void arch_ioreq_server_destroy(struct ioreq_server *s) >> +{ >> +} >> + >> +static inline int arch_ioreq_server_map_mem_type(struct domain *d, >> + struct ioreq_server *s, >> + uint32_t flags) >> +{ >> + return -EOPNOTSUPP; >> +} >> + >> +static inline bool arch_ioreq_server_destroy_all(struct domain *d) >> +{ >> + return true; >> +} >> + >> +static inline int arch_ioreq_server_get_type_addr(const struct domain *d, >> + const ioreq_t *p, >> + uint8_t *type, >> + uint64_t *addr) >> +{ >> + if ( p->type != IOREQ_TYPE_COPY && p->type != IOREQ_TYPE_PIO ) >> + return -EINVAL; >> + >> + *type = (p->type == IOREQ_TYPE_PIO) ? >> + XEN_DMOP_IO_RANGE_PORT : XEN_DMOP_IO_RANGE_MEMORY; >> + *addr = p->addr; > This function is not used in this patch and PIOs are left unimplemented > according to a few comments, so I am puzzled by this code here. Do we > need it? Yes. It is called from ioreq_server_select (common/ioreq.c). I could just skip PIO case and use *type = XEN_DMOP_IO_RANGE_MEMORY, but I didn't want to diverge. -- Regards, Oleksandr Tyshchenko