diff options
Diffstat (limited to 'hw/i386/pc_q35.c')
| -rw-r--r-- | hw/i386/pc_q35.c | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c index 710464598e..a7f626096a 100644 --- a/hw/i386/pc_q35.c +++ b/hw/i386/pc_q35.c @@ -51,6 +51,10 @@ static bool has_pci_info; static bool has_acpi_build = true; static bool smbios_type1_defaults = true; +/* Make sure that guest addresses aligned at 1Gbyte boundaries get mapped to + * host addresses aligned at 1Gbyte boundaries. This way we can use 1GByte + * pages in the host. + */ static bool gigabyte_align = true; /* PC hardware initialisation */ @@ -93,6 +97,15 @@ static void pc_q35_init(QEMUMachineInitArgs *args) kvmclock_create(); + /* Check whether RAM fits below 4G (leaving 1/2 GByte for IO memory + * and 256 Mbytes for PCI Express Enhanced Configuration Access Mapping + * also known as MMCFG). + * If it doesn't, we need to split it in chunks below and above 4G. + * In any case, try to make sure that guest addresses aligned at + * 1G boundaries get mapped to host addresses aligned at 1G boundaries. + * For old machine types, use whatever split we used historically to avoid + * breaking migration. + */ if (args->ram_size >= 0xb0000000) { ram_addr_t lowmem = gigabyte_align ? 0x80000000 : 0xb0000000; above_4g_mem_size = args->ram_size - lowmem; |