@@ -25,6 +25,8 @@
* References:
* [1] 82371FB (PIIX) AND 82371SB (PIIX3) PCI ISA IDE XCELERATOR,
* 290550-002, Intel Corporation, April 1997.
+ * [2] 82371AB PCI-TO-ISA / IDE XCELERATOR (PIIX4), 290562-001,
+ * Intel Corporation, April 1997.
*/
#include "qemu/osdep.h"
@@ -160,6 +162,19 @@ static void pci_piix_ide_realize(PCIDevice *dev, Error **errp)
uint8_t *pci_conf = dev->config;
int rc;
+ /*
+ * Mask all IDE PCI command register bits except for Bus Master
+ * Function Enable (bit 2) and I/O Space Enable (bit 1), as the
+ * remainder are hardwired to 0 [1, p.48] [2, p.89-90].
+ *
+ * NOTE: According to the PIIX3 datasheet [1], the Memory Space
+ * Enable (MSE bit) is hardwired to 1, but this is contradicted by
+ * actual PIIX3 hardware, the datasheet itself (viz., Default
+ * Value: 0000h), and the PIIX4 datasheet [2].
+ */
+ pci_set_word(dev->wmask + PCI_COMMAND,
+ PCI_COMMAND_MASTER | PCI_COMMAND_IO);
+
pci_conf[PCI_CLASS_PROG] = 0x80; // legacy ATA mode
bmdma_setup_bar(d);
@@ -176,6 +176,7 @@ static QPCIDevice *get_pci_device(QTestState *qts, QPCIBar *bmdma_bar,
*ide_bar = qpci_legacy_iomap(dev, IDE_BASE);
+ dev->command_disabled = PCI_COMMAND_MEMORY;
qpci_device_enable(dev);
return dev;
One method to enable PCI bus mastering for IDE controllers, often used by x86 firmware, is to write 0x7 to the PCI command register. Neither the PIIX3 specification nor actual hardware (a Tyan S1686D system) permit modification of the Memory Space Enable (MSE) bit, 1, and thus the command register would be left in an unspecified state without this patch. * hw/ide/piix.c a) Add a reference to the PIIX4 data sheet. b) Mask the MSE bit using the QEMU PCI device wmask field. * tests/qtest/ide-test.c Use the command_disabled field of the QPCIDevice testing model to indicate that PCI_COMMAND_MEMORY is hardwired in the PIIX3/4 IDE controller. Signed-off-by: Lev Kujawski <lkujaw@member.fsf.org> --- hw/ide/piix.c | 15 +++++++++++++++ tests/qtest/ide-test.c | 1 + 2 files changed, 16 insertions(+)