When converting GPA ranges containing MMIO holes, the general intended logic is to skip MMIO ranges as long as it is a private->shared conversion, and to fail otherwise.
To better enable some future refactorings to address bugs in the current code, go ahead and consolidate all of the MMIO handling to a self-contained helper. The only intended functional change is that the error message for shared->private conversion of MMIO ranges corresponding to a non-RAM/non-ROM region now report the range of the region that specifically caused the failure, as opposed to reporting the entire conversion range. Signed-off-by: Michael Roth <[email protected]> --- accel/kvm/kvm-all.c | 96 ++++++++++++++++++++++++++++++--------------- 1 file changed, 64 insertions(+), 32 deletions(-) diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c index 70605a8d10..0b59ba0d3c 100644 --- a/accel/kvm/kvm-all.c +++ b/accel/kvm/kvm-all.c @@ -3334,6 +3334,67 @@ static void kvm_eat_signals(CPUState *cpu) } while (sigismember(&chkset, SIG_IPI)); } +/* + * This handles checking whether a conversion overlaps with any holes in + * the given section/range, and indicates whether or not the section/range + * can be safely skipped (which is generally allowed as long as the + * conversion is private->shared and not the other way around). + * + * Returns 0 if section is normal guest-memfd-backed memory, or is a hole or + * non-RAM/ROM region that should be skipped as MMIO. In the latter case, the + * 'skip' parameter will be set. Returns < 0 if the conversion request is not + * valid. + */ +static int handle_memory_hole(MemoryRegionSection *section, bool to_private, + bool *skip) +{ + MemoryRegion *mr = section->mr; + + if (!mr) { + /* + * TDX requires vMMIO region to be shared to inject #VE to guest. + * OVMF issues conservatively MapGPA(shared) on 32bit PCI MMIO + * region, and vIO-APIC 0xFEC00000 4K page. + * OVMF assigns 32bit PCI MMIO region to + * [top of low memory: typically 2GB=0xC000000, 0xFC00000) + * + * If the current lookup failed to find any regions, then skip the + * entire remaining range as a hole/MMIO. + */ + if (!to_private) { + *skip = true; + return 0; + } + return -EINVAL; + } + + /* + * Because vMMIO region must be shared, guest TD may convert vMMIO + * region to shared explicitly. Don't complain such case. See + * memory_region_type() for checking if the region is MMIO region. + */ + if (!memory_region_has_guest_memfd_private(mr)) { + if (!to_private && + !memory_region_is_ram(mr) && + !memory_region_is_ram_device(mr) && + !memory_region_is_rom(mr) && + !memory_region_is_romd(mr)) { + *skip = true; + return 0; + } else { + error_report("Convert non guest_memfd backed memory region " + "(0x%"HWADDR_PRIx" + 0x%"HWADDR_PRIx") to %s", + section->offset_within_address_space, + int128_get64(section->size), + to_private ? "private" : "shared"); + return -EINVAL; + } + } + + *skip = false; + return 0; +} + int kvm_convert_memory(hwaddr start, hwaddr size, bool to_private) { MemoryRegionSection section; @@ -3341,6 +3402,7 @@ int kvm_convert_memory(hwaddr start, hwaddr size, bool to_private) MemoryRegion *mr; RAMBlock *rb; void *addr; + bool skip; int ret = -EINVAL; trace_kvm_convert_memory(start, size, to_private ? "shared_to_private" : "private_to_shared"); @@ -3356,39 +3418,9 @@ int kvm_convert_memory(hwaddr start, hwaddr size, bool to_private) section = memory_region_find(get_system_memory(), start, size); mr = section.mr; - if (!mr) { - /* - * Ignore converting non-assigned region to shared. - * - * TDX requires vMMIO region to be shared to inject #VE to guest. - * OVMF issues conservatively MapGPA(shared) on 32bit PCI MMIO region, - * and vIO-APIC 0xFEC00000 4K page. - * OVMF assigns 32bit PCI MMIO region to - * [top of low memory: typically 2GB=0xC000000, 0xFC00000) - */ - if (!to_private) { - return 0; - } - return ret; - } - if (!memory_region_has_guest_memfd_private(mr)) { - /* - * Because vMMIO region must be shared, guest TD may convert vMMIO - * region to shared explicitly. Don't complain such case. See - * memory_region_type() for checking if the region is MMIO region. - */ - if (!to_private && - !memory_region_is_ram(mr) && - !memory_region_is_ram_device(mr) && - !memory_region_is_rom(mr) && - !memory_region_is_romd(mr)) { - ret = 0; - } else { - error_report("Convert non guest_memfd backed memory region " - "(0x%"HWADDR_PRIx" ,+ 0x%"HWADDR_PRIx") to %s", - start, size, to_private ? "private" : "shared"); - } + ret = handle_memory_hole(§ion, to_private, &skip); + if (ret || skip) { goto out_unref; } -- 2.43.0
