diff options
Diffstat (limited to 'tools/firmware')
| -rw-r--r-- | tools/firmware/hvmloader/pci.c | 49 |
1 files changed, 47 insertions, 2 deletions
diff --git a/tools/firmware/hvmloader/pci.c b/tools/firmware/hvmloader/pci.c index 9253b0b4c6..627e8cbcb6 100644 --- a/tools/firmware/hvmloader/pci.c +++ b/tools/firmware/hvmloader/pci.c @@ -27,6 +27,8 @@ #include <xen/memory.h> #include <xen/hvm/ioreq.h> +#include <xen/hvm/hvm_xs_strings.h> +#include <stdbool.h> unsigned long pci_mem_start = PCI_MEM_START; unsigned long pci_mem_end = PCI_MEM_END; @@ -57,6 +59,32 @@ void pci_setup(void) } *bars = (struct bars *)scratch_start; unsigned int i, nr_bars = 0; + const char *s; + /* + * Do we allow hvmloader to relocate guest memory in order to + * increase the size of the lowmem MMIO hole? Defaulting to 1 + * here will mean that non-libxl toolstacks (including xend and + * home-grown ones) means that those using qemu-xen will still + * experience the memory relocation bug described below; but it + * also means that those using qemu-traditional will *not* + * experience any change; and it also means that there is a + * work-around for those using qemu-xen, namely switching to + * qemu-traditional. + * + * If we defaulted to 0, and failing to resize the hole caused any + * problems with qemu-traditional, then there is no work-around. + * + * Since xend can only use qemu-traditional, I think this is the + * option that will have the least impact. + */ + bool allow_memory_relocate = 1; + + s = xenstore_read(HVM_XS_ALLOW_MEMORY_RELOCATE, NULL); + if ( s ) + allow_memory_relocate = strtoll(s, NULL, 0); + printf("Relocating guest memory for lowmem MMIO space %s\n", + allow_memory_relocate?"enabled":"disabled"); + /* Program PCI-ISA bridge with appropriate link routes. */ isa_irq = 0; for ( link = 0; link < 4; link++ ) @@ -208,8 +236,25 @@ void pci_setup(void) pci_writew(devfn, PCI_COMMAND, cmd); } - while ( (mmio_total > (pci_mem_end - pci_mem_start)) && - ((pci_mem_start << 1) != 0) ) + /* + * At the moment qemu-xen can't deal with relocated memory regions. + * It's too close to the release to make a proper fix; for now, + * only allow the MMIO hole to grow large enough to move guest memory + * if we're running qemu-traditional. Items that don't fit will be + * relocated into the 64-bit address space. + * + * This loop now does the following: + * - If allow_memory_relocate, increase the MMIO hole until it's + * big enough, or until it's 2GiB + * - If !allow_memory_relocate, increase the MMIO hole until it's + * big enough, or until it's 2GiB, or until it overlaps guest + * memory + */ + while ( (mmio_total > (pci_mem_end - pci_mem_start)) + && ((pci_mem_start << 1) != 0) + && (allow_memory_relocate + || (((pci_mem_start << 1) >> PAGE_SHIFT) + >= hvm_info->low_mem_pgend)) ) pci_mem_start <<= 1; if ( mmio_total > (pci_mem_end - pci_mem_start) ) |