On Tue, Aug 29, 2023 at 11:19:44PM +0000, Volodymyr Babchuk wrote:
> From: Oleksandr Andrushchenko <[email protected]>
>
> Take into account guest's BAR view and program its p2m accordingly:
> gfn is guest's view of the BAR and mfn is the physical BAR value.
> This way hardware domain sees physical BAR values and guest sees
> emulated ones.
>
> Hardware domain continues getting the BARs identity mapped, while for
> domUs the BARs are mapped at the requested guest address without
> modifying the BAR address in the device PCI config space.
>
> Signed-off-by: Oleksandr Andrushchenko <[email protected]>
> Signed-off-by: Volodymyr Babchuk <[email protected]>
> ---
> Since v9:
> - Extended the commit message
> - Use bar->guest_addr in modify_bars
> - Extended printk error message in map_range
> - Moved map_data initialization so .bar can be initialized during declaration
> Since v5:
> - remove debug print in map_range callback
> - remove "identity" from the debug print
> Since v4:
> - moved start_{gfn|mfn} calculation into map_range
> - pass vpci_bar in the map_data instead of start_{gfn|mfn}
> - s/guest_addr/guest_reg
> Since v3:
> - updated comment (Roger)
> - removed gfn_add(map->start_gfn, rc); which is wrong
> - use v->domain instead of v->vpci.pdev->domain
> - removed odd e.g. in comment
> - s/d%d/%pd in altered code
> - use gdprintk for map/unmap logs
> Since v2:
> - improve readability for data.start_gfn and restructure ?: construct
> Since v1:
> - s/MSI/MSI-X in comments
> ---
> xen/drivers/vpci/header.c | 52 ++++++++++++++++++++++++++++-----------
> 1 file changed, 38 insertions(+), 14 deletions(-)
>
> diff --git a/xen/drivers/vpci/header.c b/xen/drivers/vpci/header.c
> index 3cc6a96849..1e82217200 100644
> --- a/xen/drivers/vpci/header.c
> +++ b/xen/drivers/vpci/header.c
> @@ -33,6 +33,7 @@
>
> struct map_data {
> struct domain *d;
> + const struct vpci_bar *bar;
> bool map;
> };
>
> @@ -44,6 +45,12 @@ static int cf_check map_range(
>
> for ( ; ; )
> {
> + /* Start address of the BAR as seen by the guest. */
> + gfn_t start_gfn = _gfn(PFN_DOWN(is_hardware_domain(map->d)
> + ? map->bar->addr
> + : map->bar->guest_addr));
> + /* Physical start address of the BAR. */
> + mfn_t start_mfn = _mfn(PFN_DOWN(map->bar->addr));
Both of those should be declared outside of the loop, as there's no
need to (re)calculate them at each iteration.
Also start_gfn likely wants to be unsigned long? All the usages of it
in the patch convert it to integer by using gfn_x().
> unsigned long size = e - s + 1;
>
> if ( !iomem_access_permitted(map->d, s, e) )
> @@ -63,6 +70,13 @@ static int cf_check map_range(
> return rc;
> }
>
> + /*
> + * Ranges to be mapped don't always start at the BAR start address,
> as
> + * there can be holes or partially consumed ranges. Account for the
> + * offset of the current address from the BAR start.
> + */
> + start_mfn = mfn_add(start_mfn, s - gfn_x(start_gfn));
This should then be a local loop variable with a different name.
> +
> /*
> * ARM TODOs:
> * - On ARM whether the memory is prefetchable or not should be
> passed
> @@ -72,8 +86,8 @@ static int cf_check map_range(
> * - {un}map_mmio_regions doesn't support preemption.
> */
>
> - rc = map->map ? map_mmio_regions(map->d, _gfn(s), size, _mfn(s))
> - : unmap_mmio_regions(map->d, _gfn(s), size, _mfn(s));
> + rc = map->map ? map_mmio_regions(map->d, _gfn(s), size, start_mfn)
> + : unmap_mmio_regions(map->d, _gfn(s), size, start_mfn);
> if ( rc == 0 )
> {
> *c += size;
> @@ -82,8 +96,9 @@ static int cf_check map_range(
> if ( rc < 0 )
> {
> printk(XENLOG_G_WARNING
> - "Failed to identity %smap [%lx, %lx] for d%d: %d\n",
> - map->map ? "" : "un", s, e, map->d->domain_id, rc);
> + "Failed to %smap [%lx (%lx), %lx (%lx)] for %pd: %d\n",
I think we would usually write such mapping messages as:
[start gfn, end gfn] -> [start mfn, end mfn]
So:
"Failed to %smap [%lx, %lx] -> [%lx, %lx] for %pd: %d\n"
> + map->map ? "" : "un", s, mfn_x(start_mfn), e,
> + mfn_x(start_mfn) + size, map->d, rc);
> break;
> }
> ASSERT(rc < size);
> @@ -162,10 +177,6 @@ static void modify_decoding(const struct pci_dev *pdev,
> uint16_t cmd,
> bool vpci_process_pending(struct vcpu *v)
> {
> struct pci_dev *pdev = v->vpci.pdev;
> - struct map_data data = {
> - .d = v->domain,
> - .map = v->vpci.cmd & PCI_COMMAND_MEMORY,
> - };
> struct vpci_header *header = NULL;
> unsigned int i;
>
> @@ -177,6 +188,11 @@ bool vpci_process_pending(struct vcpu *v)
> for ( i = 0; i < ARRAY_SIZE(header->bars); i++ )
> {
> struct vpci_bar *bar = &header->bars[i];
> + struct map_data data = {
> + .d = v->domain,
> + .map = v->vpci.cmd & PCI_COMMAND_MEMORY,
> + .bar = bar,
> + };
> int rc;
>
> if ( rangeset_is_empty(bar->mem) )
> @@ -229,7 +245,6 @@ bool vpci_process_pending(struct vcpu *v)
> static int __init apply_map(struct domain *d, const struct pci_dev *pdev,
> uint16_t cmd)
> {
> - struct map_data data = { .d = d, .map = true };
> struct vpci_header *header = &pdev->vpci->header;
> int rc = 0;
> unsigned int i;
> @@ -239,6 +254,7 @@ static int __init apply_map(struct domain *d, const
> struct pci_dev *pdev,
> for ( i = 0; i < ARRAY_SIZE(header->bars); i++ )
> {
> struct vpci_bar *bar = &header->bars[i];
> + struct map_data data = { .d = d, .map = true, .bar = bar };
>
> if ( rangeset_is_empty(bar->mem) )
> continue;
> @@ -306,12 +322,18 @@ static int modify_bars(const struct pci_dev *pdev,
> uint16_t cmd, bool rom_only)
> * First fill the rangesets with the BAR of this device or with the ROM
> * BAR only, depending on whether the guest is toggling the memory decode
> * bit of the command register, or the enable bit of the ROM BAR
> register.
> + *
> + * For non-hardware domain we use guest physical addresses.
> */
> for ( i = 0; i < ARRAY_SIZE(header->bars); i++ )
> {
> struct vpci_bar *bar = &header->bars[i];
> unsigned long start = PFN_DOWN(bar->addr);
> unsigned long end = PFN_DOWN(bar->addr + bar->size - 1);
> + unsigned long start_guest =
> PFN_DOWN(is_hardware_domain(pdev->domain) ?
> + bar->addr : bar->guest_addr);
> + unsigned long end_guest = PFN_DOWN((is_hardware_domain(pdev->domain)
> ?
> + bar->addr : bar->guest_addr) + bar->size -
> 1);
>
> if ( !bar->mem )
> continue;
> @@ -331,11 +353,11 @@ static int modify_bars(const struct pci_dev *pdev,
> uint16_t cmd, bool rom_only)
> continue;
> }
>
> - rc = rangeset_add_range(bar->mem, start, end);
> + rc = rangeset_add_range(bar->mem, start_guest, end_guest);
> if ( rc )
> {
> printk(XENLOG_G_WARNING "Failed to add [%lx, %lx]: %d\n",
> - start, end, rc);
> + start_guest, end_guest, rc);
> return rc;
> }
>
> @@ -352,7 +374,7 @@ static int modify_bars(const struct pci_dev *pdev,
> uint16_t cmd, bool rom_only)
> {
> gprintk(XENLOG_WARNING,
> "%pp: failed to remove overlapping range [%lx, %lx]:
> %d\n",
> - &pdev->sbdf, start, end, rc);
> + &pdev->sbdf, start_guest, end_guest, rc);
> return rc;
> }
> }
I think you are missing a change to adjust vmsix_table_base() to also
return the MSI-X table position in guest address space for domUs, or
else the MSI-X overlapping range checks for domUs are wrong.
Thanks, Roger.
