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Re: [Qemu-devel] [PATCH] xen-hvm: stop faking I/O to access PCI config s
From: |
Anthony PERARD |
Subject: |
Re: [Qemu-devel] [PATCH] xen-hvm: stop faking I/O to access PCI config space |
Date: |
Thu, 17 May 2018 17:30:53 +0100 |
User-agent: |
Mutt/1.9.5 (2018-04-13) |
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
> 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?
> + 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