From 3b586fc67d5eb2c3a18cdd3febc25c09de2a11a7 Mon Sep 17 00:00:00 2001 From: Paul Durrant Date: Wed, 1 Oct 2014 11:37:06 +0200 Subject: [PATCH] ioreq-server: handle the lack of a default emulator properly I started porting QEMU over to use the new ioreq server API and hit a problem with PCI bus enumeration. Because, with my patches, QEMU only registers to handle config space accesses for the PCI device it implements all other attempts by the guest to access 0xcfc go nowhere and this was causing the vcpu to wedge up because nothing was completing the I/O. This patch introduces an I/O completion handler into the hypervisor for the case where no ioreq server matches a particular request. Read requests are completed with 0xf's in the data buffer, writes and all other I/O req types are ignored. Signed-off-by: Paul Durrant Reviewed-by: Jan Beulich --- xen/arch/x86/hvm/hvm.c | 35 ++++++++++++++++++++++++++++++++--- 1 file changed, 32 insertions(+), 3 deletions(-) diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c index 7e2d5d106e..43471de71d 100644 --- a/xen/arch/x86/hvm/hvm.c +++ b/xen/arch/x86/hvm/hvm.c @@ -2332,8 +2332,7 @@ static struct hvm_ioreq_server *hvm_select_ioreq_server(struct domain *d, if ( list_empty(&d->arch.hvm_domain.ioreq_server.list) ) return NULL; - if ( list_is_singular(&d->arch.hvm_domain.ioreq_server.list) || - (p->type != IOREQ_TYPE_COPY && p->type != IOREQ_TYPE_PIO) ) + if ( p->type != IOREQ_TYPE_COPY && p->type != IOREQ_TYPE_PIO ) return d->arch.hvm_domain.default_ioreq_server; cf8 = d->arch.hvm_domain.pci_cf8; @@ -2564,12 +2563,42 @@ bool_t hvm_send_assist_req_to_ioreq_server(struct hvm_ioreq_server *s, return 0; } +static bool_t hvm_complete_assist_req(ioreq_t *p) +{ + switch ( p->type ) + { + case IOREQ_TYPE_COPY: + case IOREQ_TYPE_PIO: + if ( p->dir == IOREQ_READ ) + { + if ( !p->data_is_ptr ) + p->data = ~0ul; + else + { + int i, step = p->df ? -p->size : p->size; + uint32_t data = ~0; + + for ( i = 0; i < p->count; i++ ) + hvm_copy_to_guest_phys(p->data + step * i, &data, + p->size); + } + } + /* FALLTHRU */ + default: + p->state = STATE_IORESP_READY; + hvm_io_assist(p); + break; + } + + return 1; +} + bool_t hvm_send_assist_req(ioreq_t *p) { struct hvm_ioreq_server *s = hvm_select_ioreq_server(current->domain, p); if ( !s ) - return 0; + return hvm_complete_assist_req(p); return hvm_send_assist_req_to_ioreq_server(s, p); } -- 2.30.2