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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [PATCH v4 3/4] vpci: allow BAR map/unmap without affecting memory decoding bit
Introduce 'bool map' and allow invoking modify_bars() without changing the memory decoding bit. This will allow hardware domain to reposition BARs without affecting the memory decoding bit. Signed-off-by: Stewart Hildebrand <stewart.hildebrand@xxxxxxx> --- This also lays some groundwork to allow domUs to toggle the guest view without affecting hardware, a step toward addressing the FIXME in [1]. [1] https://lore.kernel.org/xen-devel/20250814160358.95543-4-roger.pau@xxxxxxxxxx/ v3->v4: * rebase on dynamically allocated map queue v2->v3: * use bool * switch to task->map in more places v1->v2: * new patch --- xen/drivers/vpci/header.c | 43 +++++++++++++++++++++------------------ xen/include/xen/vpci.h | 1 + 2 files changed, 24 insertions(+), 20 deletions(-) diff --git a/xen/drivers/vpci/header.c b/xen/drivers/vpci/header.c index 146915e28c50..20fe380552f4 100644 --- a/xen/drivers/vpci/header.c +++ b/xen/drivers/vpci/header.c @@ -117,11 +117,12 @@ static int cf_check map_range( * BAR's enable bit has changed with the memory decoding bit already enabled. * If rom_only is not set then it's the memory decoding bit that changed. */ -static void modify_decoding(const struct pci_dev *pdev, uint16_t cmd, - bool rom_only) +static void modify_decoding(const struct pci_dev *pdev, + struct vpci_map_task *task) { struct vpci_header *header = &pdev->vpci->header; - bool map = cmd & PCI_COMMAND_MEMORY; + bool rom_only = task->rom_only; + bool map = task->map; unsigned int i; for ( i = 0; i < ARRAY_SIZE(header->bars); i++ ) @@ -168,7 +169,7 @@ static void modify_decoding(const struct pci_dev *pdev, uint16_t cmd, if ( !rom_only ) { - pci_conf_write16(pdev->sbdf, PCI_COMMAND, cmd); + pci_conf_write16(pdev->sbdf, PCI_COMMAND, task->cmd); header->bars_mapped = map; } else @@ -188,7 +189,7 @@ static int vpci_process_map_task(const struct pci_dev *pdev, struct rangeset *mem = bar->mem; struct map_data data = { .d = pdev->domain, - .map = task->cmd & PCI_COMMAND_MEMORY, + .map = task->map, .bar = bar, }; int rc; @@ -203,9 +204,11 @@ static int vpci_process_map_task(const struct pci_dev *pdev, if ( rc ) { - spin_lock(&pdev->vpci->lock); /* Disable memory decoding unconditionally on failure. */ - modify_decoding(pdev, task->cmd & ~PCI_COMMAND_MEMORY, false); + task->cmd &= ~PCI_COMMAND_MEMORY; + task->map = false; + spin_lock(&pdev->vpci->lock); + modify_decoding(pdev, task); spin_unlock(&pdev->vpci->lock); if ( !is_hardware_domain(pdev->domain) ) @@ -216,7 +219,7 @@ static int vpci_process_map_task(const struct pci_dev *pdev, } spin_lock(&pdev->vpci->lock); - modify_decoding(pdev, task->cmd, task->rom_only); + modify_decoding(pdev, task); spin_unlock(&pdev->vpci->lock); return 0; @@ -328,13 +331,14 @@ static int __init apply_map(struct domain *d, const struct pci_dev *pdev, } } if ( !rc ) - modify_decoding(pdev, task->cmd, false); + modify_decoding(pdev, task); return rc; } static struct vpci_map_task *alloc_map_task(const struct pci_dev *pdev, - uint16_t cmd, bool rom_only) + uint16_t cmd, bool rom_only, + bool map) { struct vpci_map_task *task; unsigned int i; @@ -364,6 +368,7 @@ static struct vpci_map_task *alloc_map_task(const struct pci_dev *pdev, task->cmd = cmd; task->rom_only = rom_only; + task->map = map; return task; } @@ -391,7 +396,8 @@ static void defer_map(const struct pci_dev *pdev, struct vpci_map_task *task) raise_softirq(SCHEDULE_SOFTIRQ); } -static int modify_bars(const struct pci_dev *pdev, uint16_t cmd, bool rom_only) +static int modify_bars(const struct pci_dev *pdev, uint16_t cmd, bool rom_only, + bool map) { struct vpci_header *header = &pdev->vpci->header; struct pci_dev *tmp; @@ -403,7 +409,7 @@ static int modify_bars(const struct pci_dev *pdev, uint16_t cmd, bool rom_only) ASSERT(rw_is_write_locked(&pdev->domain->pci_lock)); - task = alloc_map_task(pdev, cmd, rom_only); + task = alloc_map_task(pdev, cmd, rom_only, map); if ( !task ) return -ENOMEM; @@ -602,7 +608,7 @@ static int modify_bars(const struct pci_dev *pdev, uint16_t cmd, bool rom_only) * be called iff the memory decoding bit is enabled, thus the operation * will always be to establish mappings and process all the BARs. */ - ASSERT((cmd & PCI_COMMAND_MEMORY) && !rom_only); + ASSERT(map && !rom_only); rc = apply_map(pdev->domain, pdev, task); destroy_map_task(task); return rc; @@ -646,7 +652,7 @@ static void cf_check cmd_write( * memory decoding bit has not been changed, so leave everything as-is, * hoping the guest will realize and try again. */ - modify_bars(pdev, cmd, false); + modify_bars(pdev, cmd, false, cmd & PCI_COMMAND_MEMORY); else pci_conf_write16(pdev->sbdf, reg, cmd); } @@ -810,11 +816,8 @@ static void cf_check rom_write( header->rom_enabled = new_enabled; pci_conf_write32(pdev->sbdf, reg, val); } - /* - * Pass PCI_COMMAND_MEMORY or 0 to signal a map/unmap request, note that - * this fabricated command is never going to be written to the register. - */ - else if ( modify_bars(pdev, new_enabled ? PCI_COMMAND_MEMORY : 0, true) ) + /* Note that the command value 0 will never be written to the register */ + else if ( modify_bars(pdev, 0, true, new_enabled) ) /* * No memory has been added or removed from the p2m (because the actual * p2m changes are deferred in defer_map) and the ROM enable bit has @@ -1004,7 +1007,7 @@ int vpci_init_header(struct pci_dev *pdev) goto fail; } - return (cmd & PCI_COMMAND_MEMORY) ? modify_bars(pdev, cmd, false) : 0; + return (cmd & PCI_COMMAND_MEMORY) ? modify_bars(pdev, cmd, false, true) : 0; fail: pci_conf_write16(pdev->sbdf, PCI_COMMAND, cmd); diff --git a/xen/include/xen/vpci.h b/xen/include/xen/vpci.h index e34f7abe6da2..e6d40827a43a 100644 --- a/xen/include/xen/vpci.h +++ b/xen/include/xen/vpci.h @@ -164,6 +164,7 @@ struct vpci_map_task { } bars[ARRAY_SIZE(((struct vpci_header *)NULL)->bars)]; uint16_t cmd; bool rom_only : 1; + bool map : 1; }; struct vpci_vcpu { -- 2.53.0
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