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Re: [PATCH V4 14/24] arm/ioreq: Introduce arch specific bits for IOREQ/DM features
On 12/01/2021 21:52, Oleksandr Tyshchenko wrote:
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 <xen/guest_access.h>
#include <xen/hypercall.h>
#include <xen/init.h>
+#include <xen/ioreq.h>
#include <xen/lib.h>
#include <xen/livepatch.h>
#include <xen/sched.h>
@@ -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
The placement of this call feels quite odd. Shouldn't this moved in case 0?
+
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..9814481 100644
--- a/xen/arch/arm/io.c
+++ b/xen/arch/arm/io.c
@@ -16,6 +16,7 @@
* GNU General Public License for more details.
*/
+#include <xen/ioreq.h>
#include <xen/lib.h>
#include <xen/spinlock.h>
#include <xen/sched.h>
@@ -23,6 +24,7 @@
#include <asm/cpuerrata.h>
#include <asm/current.h>
#include <asm/mmio.h>
+#include <asm/hvm/ioreq.h>
Shouldn't this have been included by "xen/ioreq.h"?
#include "decode.h"
@@ -123,7 +125,15 @@ 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..3c4a24d
--- /dev/null
+++ b/xen/arch/arm/ioreq.c
@@ -0,0 +1,213 @@
+/*
+ * 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 <http://www.gnu.org/licenses/>.
+ */
+
+#include <xen/domain.h>
+#include <xen/ioreq.h>
+
+#include <asm/traps.h>
+
+#include <public/hvm/ioreq.h>
+
+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;
+ }
Looking at the rest of the series, this code is going to be refactored
in patch #19 and then hardened. It would have been better to do the
refactoring first and then use it.
This helps a lot for the review and to reduce what I would call churn in
the series.
I am OK to keep it like that for this series.
+
+ set_user_reg(regs, dabt.reg, r);
+
+ 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;
With the Arm code in mind, I am a bit confused with this check. If
vio->req.state == STATE_IORESP_READY, then it would imply that the
previous I/O emulation was somehow not completed (from Xen PoV).
If you return IO_HANDLED here, then it means the we will take care of
previous I/O but the current one is going to be ignored. So shouldn't we
use the default path here as well?
+
+ 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 = VIO_mmio_completion;
+
+ return rc;
+}
+
+bool arch_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;
+}
+
+bool arch_vcpu_ioreq_completion(enum vio_completion 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
+ */
+int arch_ioreq_server_map_pages(struct ioreq_server *s)
+{
+ return -EOPNOTSUPP;
+}
+
+void arch_ioreq_server_unmap_pages(struct ioreq_server *s)
+{
+}
+
+void arch_ioreq_server_enable(struct ioreq_server *s)
+{
+}
+
+void arch_ioreq_server_disable(struct ioreq_server *s)
+{
+}
+
+void arch_ioreq_server_destroy(struct ioreq_server *s)
+{
+}
+
+int arch_ioreq_server_map_mem_type(struct domain *d,
+ struct ioreq_server *s,
+ uint32_t flags)
+{
+ return -EOPNOTSUPP;
+}
+
+void arch_ioreq_server_map_mem_type_completed(struct domain *d,
+ struct ioreq_server *s,
+ uint32_t flags)
+{
+}
+
+bool arch_ioreq_server_destroy_all(struct domain *d)
+{
+ return true;
+}
+
+bool 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 false;
+
+ *type = (p->type == IOREQ_TYPE_PIO) ?
+ XEN_DMOP_IO_RANGE_PORT : XEN_DMOP_IO_RANGE_MEMORY;
+ *addr = p->addr;
+
+ return true;
+}
+
+void arch_ioreq_domain_init(struct domain *d)
+{
+}
+
+/*
+ * 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 <xen/hypercall.h>
#include <xen/init.h>
#include <xen/iocap.h>
+#include <xen/ioreq.h>
#include <xen/irq.h>
#include <xen/lib.h>
#include <xen/mem_access.h>
@@ -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 <asm/gic.h>
#include <asm/vgic.h>
#include <asm/vpl011.h>
+#include <public/hvm/dm_op.h>
May I ask, why do you need to include dm_op.h here?
#include <public/hvm/params.h>
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..19e1247
--- /dev/null
+++ b/xen/include/asm-arm/hvm/ioreq.h
Shouldn't this directly be under asm-arm/ rather than asm-arm/hvm/ as
the IOREQ is now meant to be agnostic?
@@ -0,0 +1,72 @@
+/*
+ * 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 <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __ASM_ARM_HVM_IOREQ_H__
+#define __ASM_ARM_HVM_IOREQ_H__
+
+#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
+
+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)
+{
+}
+
+/* This correlation must not be altered */
+#define IOREQ_STATUS_HANDLED IO_HANDLED
+#define IOREQ_STATUS_UNHANDLED IO_UNHANDLED
+#define IOREQ_STATUS_RETRY IO_RETRY
+
+#endif /* __ASM_ARM_HVM_IOREQ_H__ */
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/xen/include/asm-arm/mmio.h b/xen/include/asm-arm/mmio.h
index 8dbfb27..7ab873c 100644
--- a/xen/include/asm-arm/mmio.h
+++ b/xen/include/asm-arm/mmio.h
@@ -37,6 +37,7 @@ enum io_state
IO_ABORT, /* The IO was handled by the helper and led to an abort.
*/
IO_HANDLED, /* The IO was successfully handled by the helper. */
IO_UNHANDLED, /* The IO was not handled by the helper. */
+ IO_RETRY, /* Retry the emulation for some reason */
};
typedef int (*mmio_read_t)(struct vcpu *v, mmio_info_t *info,
--
Julien Grall
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