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hw/scsi/esp-pci: use correct address register for PCI DMA transfers

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The current code in esp_pci_dma_memory_rw() sets the DMA address to the value
of the DMA_SPA (Starting Physical Address) register which is incorrect: this
means that for each callback from the SCSI layer the DMA address is set back
to the starting address.

In the case where only a single SCSI callback occurs (currently for transfer
lengths < 128kB) this works fine, however for larger transfers the DMA address
wraps back to the initial starting address, corrupting the buffer holding the
data transferred to the guest.

Fix esp_pci_dma_memory_rw() to use the DMA_WAC (Working Address Counter) for
the DMA address which is correctly incremented across multiple SCSI layer
transfers.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Message-ID: <20240112131529.515642-2-mark.cave-ayland@ilande.co.uk>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
This commit is contained in:
Mark Cave-Ayland 2024-01-12 13:15:26 +00:00 committed by Philippe Mathieu-Daudé
parent 7ebbd9d0b6
commit 84a6835e00
1 changed files with 1 additions and 1 deletions
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2
hw/scsi/esp-pci.c
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@ -275,7 +275,7 @@ static void esp_pci_dma_memory_rw(PCIESPState *pci, uint8_t *buf, int len,
qemu_log_mask(LOG_UNIMP, "am53c974: MDL transfer not implemented\n");
}
addr = pci->dma_regs[DMA_SPA];
addr = pci->dma_regs[DMA_WAC];
if (pci->dma_regs[DMA_WBC] < len) {
len = pci->dma_regs[DMA_WBC];
}