Kernel/AHCI: Don't set the PRDBC when accessing the device

This resulted in fatal error when trying to write to real hard drive
I tested, so we only set the counts in the scatter/gather list later.
This commit is contained in:
Liav A 2021-03-19 03:08:23 +02:00 committed by Andreas Kling
parent 0b1fa97b30
commit 6c03fdc1ef
Notes: sideshowbarker 2024-07-18 21:11:50 +09:00

View File

@ -536,7 +536,7 @@ bool AHCIPort::access_device(AsyncBlockDeviceRequest::RequestType direction, u64
auto* command_list_entries = (volatile AHCI::CommandHeader*)m_command_list_region->vaddr().as_ptr();
command_list_entries[unused_command_header.value()].ctba = m_command_table_pages[unused_command_header.value()].paddr().get();
command_list_entries[unused_command_header.value()].ctbau = 0;
command_list_entries[unused_command_header.value()].prdbc = (block_count * m_connected_device->block_size());
command_list_entries[unused_command_header.value()].prdbc = 0;
command_list_entries[unused_command_header.value()].prdtl = m_current_scatter_list->scatters_count();
// Note: we must set the correct Dword count in this register. Real hardware
@ -555,12 +555,20 @@ bool AHCIPort::access_device(AsyncBlockDeviceRequest::RequestType direction, u64
memset(const_cast<u8*>(command_table.command_fis), 0, 64);
size_t scatter_entry_index = 0;
size_t data_transfer_count = (block_count * m_connected_device->block_size());
for (auto scatter_page : m_current_scatter_list->vmobject().physical_pages()) {
VERIFY(data_transfer_count != 0);
VERIFY(scatter_page);
dbgln_if(AHCI_DEBUG, "AHCI Port {}: Add a transfer scatter entry @ {}", representative_port_index(), scatter_page->paddr());
command_table.descriptors[scatter_entry_index].base_high = 0;
command_table.descriptors[scatter_entry_index].base_low = scatter_page->paddr().get();
command_table.descriptors[scatter_entry_index].byte_count = PAGE_SIZE - 1;
if (data_transfer_count <= PAGE_SIZE) {
command_table.descriptors[scatter_entry_index].byte_count = data_transfer_count - 1;
data_transfer_count = 0;
} else {
command_table.descriptors[scatter_entry_index].byte_count = PAGE_SIZE - 1;
data_transfer_count -= PAGE_SIZE;
}
scatter_entry_index++;
}
command_table.descriptors[scatter_entry_index].byte_count = (PAGE_SIZE - 1) | (1 << 31);