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Re: [Qemu-devel] [PATCH v5 1/1] xen-hvm.c: Add support for Xen access to
From: |
Paul Durrant |
Subject: |
Re: [Qemu-devel] [PATCH v5 1/1] xen-hvm.c: Add support for Xen access to vmport |
Date: |
Mon, 20 Oct 2014 12:30:06 +0000 |
> -----Original Message-----
> From: Don Slutz [mailto:address@hidden
> Sent: 20 October 2014 13:19
> To: address@hidden; Paul Durrant
> Cc: address@hidden; Alexander Graf; Andreas Färber;
> Anthony Liguori; Don Slutz; Marcel Apfelbaum; Markus Armbruster; Michael
> S. Tsirkin; Stefano Stabellini
> Subject: [PATCH v5 1/1] xen-hvm.c: Add support for Xen access to vmport
>
> This adds synchronisation of the 6 vcpu registers (only 32bits of
> them) that vmport.c needs between Xen and QEMU.
>
> This is to avoid a 2nd and 3rd exchange between QEMU and Xen to
> fetch and put these 6 vcpu registers used by the code in vmport.c
> and vmmouse.c
>
> The registers are passed in the new shared page provided by
> HVM_PARAM_VMPORT_REGS_PFN.
>
> Add new array to XenIOState that allows selection of current_cpu by
> vcpu id.
>
> Now pass XenIOState to handle_ioreq().
>
> Add new routines regs_to_cpu(), regs_from_cpu(), and
> handle_vmport_ioreq().
>
> Signed-off-by: Don Slutz <address@hidden>
> ---
> v5:
> vmware_ioreq_t struct is not really a request any more. Maybe
> vmware_regs_t?
> Renamed various parts from vmware_ioreq to vmware_regs. Also
> HVM_PARAM_VMPORT_IOREQ_PFN to
> HVM_PARAM_VMPORT_REGS_PFN.
> cpu_by_ioreq_id name implies the array is indexed by an id
> carries in the ioreq.
> Renamed cpu_by_ioreq_id to cpu_by_vcpu_id.
> Is cpu_get_vmport_ioreq_from_shared_memory worth its own
> function?
> Moved in-line.
> I don't think you need the barrier anyway.
> Dropped the barrier.
> Oh, I now realize you mean the same theoretical rather than
> actual limit, in which case this can be a build time check
> anyway.
> Switch to build time check, move to a better place.
> You could avoid passing state to both of them by setting
> current_cpu here couldn't you?
> Yes, moved state usage to handle_vmport_ioreq().
> Error out if it fails with error != -ENOSYS.
> Done.
>
> v4:
> Please try to get rid of the #ifdefs.
> Moved 2 #ifdefs into hw/xen/xen_common.h
>
One possible nit, inline below, but...
Reviewed-by: Paul Durrant <address@hidden>
>
> include/hw/xen/xen_common.h | 22 +++++++++
> xen-hvm.c | 110
> ++++++++++++++++++++++++++++++++++++++++++--
> 2 files changed, 127 insertions(+), 5 deletions(-)
>
> diff --git a/include/hw/xen/xen_common.h
> b/include/hw/xen/xen_common.h
> index 07731b9..42e3d77 100644
> --- a/include/hw/xen/xen_common.h
> +++ b/include/hw/xen/xen_common.h
> @@ -164,4 +164,26 @@ void destroy_hvm_domain(bool reboot);
> /* shutdown/destroy current domain because of an error */
> void xen_shutdown_fatal_error(const char *fmt, ...) GCC_FMT_ATTR(1, 2);
>
> +#ifdef HVM_PARAM_VMPORT_REGS_PFN
> +static inline int xen_get_vmport_regs_pfn(XenXC xc, domid_t dom,
> + unsigned long *vmport_regs_pfn)
> +{
> + return xc_get_hvm_param(xc, dom,
> HVM_PARAM_VMPORT_REGS_PFN,
> + vmport_regs_pfn);
> +}
> +#else
> +static inline int xen_get_vmport_regs_pfn(XenXC xc, domid_t dom,
> + unsigned long *vmport_regs_pfn)
> +{
> + return -ENOSYS;
> +}
> +#endif
> +
> +#if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 6)
> +/* Force a compilation error if condition is true */
> +#define BUILD_BUG_ON(cond) ({ _Static_assert(!(cond), "!(" #cond ")"); })
> +#else
> +#define BUILD_BUG_ON(cond) ((void)sizeof(struct { int:-!!(cond); }))
> +#endif
> +
> #endif /* QEMU_HW_XEN_COMMON_H */
> diff --git a/xen-hvm.c b/xen-hvm.c
> index 05e522c..b5ef683 100644
> --- a/xen-hvm.c
> +++ b/xen-hvm.c
> @@ -41,6 +41,29 @@ static MemoryRegion *framebuffer;
> static bool xen_in_migration;
>
> /* Compatibility with older version */
> +
> +/* This allows QEMU to build on a system that has Xen 4.5 or earlier
> + * installed. This here (not in hw/xen/xen_common.h) because
> xen/hvm/ioreq.h
> + * needs to be included before this block and hw/xen/xen_common.h
> needs to
> + * be included before xen/hvm/ioreq.h
> + */
> +#ifndef IOREQ_TYPE_VMWARE_PORT
> +#define IOREQ_TYPE_VMWARE_PORT 3
> +struct vmware_regs {
> + uint32_t esi;
> + uint32_t edi;
> + uint32_t ebx;
> + uint32_t ecx;
> + uint32_t edx;
> +};
> +typedef struct vmware_regs vmware_regs_t;
> +
> +struct shared_vmport_iopage {
> + struct vmware_regs vcpu_vmport_regs[1];
> +};
> +typedef struct shared_vmport_iopage shared_vmport_iopage_t;
> +#endif
> +
> #if __XEN_LATEST_INTERFACE_VERSION__ < 0x0003020a
> static inline uint32_t xen_vcpu_eport(shared_iopage_t *shared_page, int i)
> {
> @@ -79,8 +102,10 @@ typedef struct XenPhysmap {
>
> typedef struct XenIOState {
> shared_iopage_t *shared_page;
> + shared_vmport_iopage_t *shared_vmport_page;
> buffered_iopage_t *buffered_io_page;
> QEMUTimer *buffered_io_timer;
> + CPUState **cpu_by_vcpu_id;
> /* the evtchn port for polling the notification, */
> evtchn_port_t *ioreq_local_port;
> /* evtchn local port for buffered io */
> @@ -101,6 +126,8 @@ typedef struct XenIOState {
> Notifier wakeup;
> } XenIOState;
>
> +static void handle_ioreq(XenIOState *state, ioreq_t *req);
> +
Do we need a forward declaration? I don't think we do.
Paul
> /* Xen specific function for piix pci */
>
> int xen_pci_slot_get_pirq(PCIDevice *pci_dev, int irq_num)
> @@ -773,7 +800,50 @@ static void cpu_ioreq_move(ioreq_t *req)
> }
> }
>
> -static void handle_ioreq(ioreq_t *req)
> +static void regs_to_cpu(vmware_regs_t *vmport_regs, ioreq_t *req)
> +{
> + X86CPU *cpu;
> + CPUX86State *env;
> +
> + cpu = X86_CPU(current_cpu);
> + env = &cpu->env;
> + env->regs[R_EAX] = req->data;
> + env->regs[R_EBX] = vmport_regs->ebx;
> + env->regs[R_ECX] = vmport_regs->ecx;
> + env->regs[R_EDX] = vmport_regs->edx;
> + env->regs[R_ESI] = vmport_regs->esi;
> + env->regs[R_EDI] = vmport_regs->edi;
> +}
> +
> +static void regs_from_cpu(vmware_regs_t *vmport_regs)
> +{
> + X86CPU *cpu = X86_CPU(current_cpu);
> + CPUX86State *env = &cpu->env;
> +
> + vmport_regs->ebx = env->regs[R_EBX];
> + vmport_regs->ecx = env->regs[R_ECX];
> + vmport_regs->edx = env->regs[R_EDX];
> + vmport_regs->esi = env->regs[R_ESI];
> + vmport_regs->edi = env->regs[R_EDI];
> +}
> +
> +static void handle_vmport_ioreq(XenIOState *state, ioreq_t *req)
> +{
> + vmware_regs_t *vmport_regs;
> +
> + assert(state->shared_vmport_page);
> + vmport_regs =
> + &state->shared_vmport_page->vcpu_vmport_regs[state-
> >send_vcpu];
> + BUILD_BUG_ON(sizeof(*req) < sizeof(*vmport_regs));
> +
> + current_cpu = state->cpu_by_vcpu_id[state->send_vcpu];
> + regs_to_cpu(vmport_regs, req);
> + cpu_ioreq_pio(req);
> + regs_from_cpu(vmport_regs);
> + current_cpu = NULL;
> +}
> +
> +static void handle_ioreq(XenIOState *state, ioreq_t *req)
> {
> if (!req->data_is_ptr && (req->dir == IOREQ_WRITE) &&
> (req->size < sizeof (target_ulong))) {
> @@ -787,6 +857,9 @@ static void handle_ioreq(ioreq_t *req)
> case IOREQ_TYPE_COPY:
> cpu_ioreq_move(req);
> break;
> + case IOREQ_TYPE_VMWARE_PORT:
> + handle_vmport_ioreq(state, req);
> + break;
> case IOREQ_TYPE_TIMEOFFSET:
> break;
> case IOREQ_TYPE_INVALIDATE:
> @@ -828,7 +901,7 @@ static int handle_buffered_iopage(XenIOState
> *state)
> req.data |= ((uint64_t)buf_req->data) << 32;
> }
>
> - handle_ioreq(&req);
> + handle_ioreq(state, &req);
>
> xen_mb();
> state->buffered_io_page->read_pointer += qw ? 2 : 1;
> @@ -857,14 +930,16 @@ static void cpu_handle_ioreq(void *opaque)
>
> handle_buffered_iopage(state);
> if (req) {
> - handle_ioreq(req);
> + handle_ioreq(state, req);
>
> if (req->state != STATE_IOREQ_INPROCESS) {
> fprintf(stderr, "Badness in I/O request ... not in service?!: "
> "%x, ptr: %x, port: %"PRIx64", "
> - "data: %"PRIx64", count: %" FMT_ioreq_size ", size: %"
> FMT_ioreq_size "\n",
> + "data: %"PRIx64", count: %" FMT_ioreq_size
> + ", size: %" FMT_ioreq_size
> + ", type: %"FMT_ioreq_size"\n",
> req->state, req->data_is_ptr, req->addr,
> - req->data, req->count, req->size);
> + req->data, req->count, req->size, req->type);
> destroy_hvm_domain(false);
> return;
> }
> @@ -904,6 +979,14 @@ static void xen_main_loop_prepare(XenIOState
> *state)
> state);
>
> if (evtchn_fd != -1) {
> + CPUState *cpu_state;
> +
> + DPRINTF("%s: Init cpu_by_vcpu_id\n", __func__);
> + CPU_FOREACH(cpu_state) {
> + DPRINTF("%s: cpu_by_vcpu_id[%d]=%p\n",
> + __func__, cpu_state->cpu_index, cpu_state);
> + state->cpu_by_vcpu_id[cpu_state->cpu_index] = cpu_state;
> + }
> qemu_set_fd_handler(evtchn_fd, cpu_handle_ioreq, NULL, state);
> }
> }
> @@ -1020,6 +1103,20 @@ int xen_hvm_init(ram_addr_t
> *below_4g_mem_size, ram_addr_t *above_4g_mem_size,
> errno, xen_xc);
> }
>
> + rc = xen_get_vmport_regs_pfn(xen_xc, xen_domid, &ioreq_pfn);
> + if (!rc) {
> + DPRINTF("shared vmport page at pfn %lx\n", ioreq_pfn);
> + state->shared_vmport_page =
> + xc_map_foreign_range(xen_xc, xen_domid, XC_PAGE_SIZE,
> + PROT_READ|PROT_WRITE, ioreq_pfn);
> + if (state->shared_vmport_page == NULL) {
> + hw_error("map shared vmport IO page returned error %d handle="
> + XC_INTERFACE_FMT, errno, xen_xc);
> + }
> + } else if (rc != -ENOSYS) {
> + hw_error("get vmport regs pfn returned error %d, rc=%d", errno, rc);
> + }
> +
> xc_get_hvm_param(xen_xc, xen_domid, HVM_PARAM_BUFIOREQ_PFN,
> &ioreq_pfn);
> DPRINTF("buffered io page at pfn %lx\n", ioreq_pfn);
> state->buffered_io_page = xc_map_foreign_range(xen_xc, xen_domid,
> XC_PAGE_SIZE,
> @@ -1028,6 +1125,9 @@ int xen_hvm_init(ram_addr_t
> *below_4g_mem_size, ram_addr_t *above_4g_mem_size,
> hw_error("map buffered IO page returned error %d", errno);
> }
>
> + /* Note: cpus is empty at this point in init */
> + state->cpu_by_vcpu_id = g_malloc0(max_cpus * sizeof(CPUState *));
> +
> state->ioreq_local_port = g_malloc0(max_cpus * sizeof (evtchn_port_t));
>
> /* FIXME: how about if we overflow the page here? */
> --
> 1.8.4