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Re: [Qemu-devel] [PATCH] xen-hvm: stop faking I/O to access PCI config s
From: |
Paul Durrant |
Subject: |
Re: [Qemu-devel] [PATCH] xen-hvm: stop faking I/O to access PCI config space |
Date: |
Fri, 18 May 2018 09:34:33 +0000 |
> -----Original Message-----
> From: Anthony PERARD [mailto:address@hidden
> Sent: 17 May 2018 17:31
> To: Paul Durrant <address@hidden>
> Cc: address@hidden; address@hidden; Stefano
> Stabellini <address@hidden>; Michael S. Tsirkin <address@hidden>;
> Marcel Apfelbaum <address@hidden>; Paolo Bonzini
> <address@hidden>; Richard Henderson <address@hidden>; Eduardo
> Habkost <address@hidden>
> Subject: Re: [PATCH] xen-hvm: stop faking I/O to access PCI config space
>
> On Thu, May 03, 2018 at 12:18:40PM +0100, Paul Durrant wrote:
> > This patch removes the current hackery where IOREQ_TYPE_PCI_CONFIG
> > reqyests are handled by faking PIO to 0xcf8 and 0xcfc and replaces it
>
> ^ requests
Ok.
>
> > with direct calls to pci_host_config_read/write_common().
> > Doing so necessitates mapping BDFs to PCIDevices but maintaining a simple
> > QLIST in xen_device_realize/unrealize() will suffice.
> >
> > NOTE: whilst config space accesses are currently limited to
> > PCI_CONFIG_SPACE_SIZE, this patch paves the way to increasing the
> > limit to PCIE_CONFIG_SPACE_SIZE when Xen gains the ability to
> > emulate MCFG table accesses.
> >
> > Signed-off-by: Paul Durrant <address@hidden>
>
> > +static void cpu_ioreq_config(XenIOState *state, ioreq_t *req)
> > +{
> > + uint32_t sbdf = req->addr >> 32;
> > + uint32_t reg = req->addr;
> > + XenPciDevice *xendev;
> > +
> > + if (req->size > sizeof(uint32_t)) {
> > + hw_error("PCI config access: bad size (%u)", req->size);
> > + }
> > +
> > + QLIST_FOREACH(xendev, &state->dev_list, entry) {
> > + unsigned int i;
> > +
> > + if (xendev->sbdf != sbdf) {
> > + continue;
> > + }
> > +
> > + if (req->dir == IOREQ_READ) {
> > + if (!req->data_is_ptr) {
> > + req->data = pci_host_config_read_common(
> > + xendev->pci_dev, reg, PCI_CONFIG_SPACE_SIZE,
> > + req->size);
> > + trace_cpu_ioreq_config_read(req, sbdf, reg, req->size,
> > + req->data);
> > + } else {
> > + for (i = 0; i < req->count; i++) {
> > + uint32_t tmp;
> > +
> > + tmp = pci_host_config_read_common(
> > + xendev->pci_dev, reg, PCI_CONFIG_SPACE_SIZE,
> > + req->size);
>
> So, if data is a pointer, we just keep reading the same address
> req->count time?
>
That's what would have happened before AFAICT, since the old scheme used port
I/O. I think you're right that it is probably worth changing to MMIO semantics
with this change though.
Paul
> > + write_phys_req_item(req->data, req, i, &tmp);
> > + }
> > + }
> > + } else if (req->dir == IOREQ_WRITE) {
> > + if (!req->data_is_ptr) {
> > + trace_cpu_ioreq_config_write(req, sbdf, reg, req->size,
> > + req->data);
> > + pci_host_config_write_common(
> > + xendev->pci_dev, reg, PCI_CONFIG_SPACE_SIZE, req->data,
> > + req->size);
> > + } else {
> > + for (i = 0; i < req->count; i++) {
> > + uint32_t tmp = 0;
> > +
> > + read_phys_req_item(req->data, req, i, &tmp);
> > + pci_host_config_write_common(
> > + xendev->pci_dev, reg, PCI_CONFIG_SPACE_SIZE, tmp,
> > + req->size);
> > + }
> > + }
> > + }
> > + }
> > +}
>
> --
> Anthony PERARD
- [Qemu-devel] [PATCH] xen-hvm: stop faking I/O to access PCI config space, Paul Durrant, 2018/05/03
- Re: [Qemu-devel] [PATCH] xen-hvm: stop faking I/O to access PCI config space, Paolo Bonzini, 2018/05/03
- Re: [Qemu-devel] [PATCH] xen-hvm: stop faking I/O to access PCI config space, Alexey G, 2018/05/03
- Re: [Qemu-devel] [PATCH] xen-hvm: stop faking I/O to access PCI config space, Paul Durrant, 2018/05/16
- Re: [Qemu-devel] [Xen-devel] [PATCH] xen-hvm: stop faking I/O to access PCI config space, Roger Pau Monné, 2018/05/16
- Re: [Qemu-devel] [PATCH] xen-hvm: stop faking I/O to access PCI config space, Anthony PERARD, 2018/05/17
- Re: [Qemu-devel] [PATCH] xen-hvm: stop faking I/O to access PCI config space,
Paul Durrant <=