Hi Marc,
On 10/3/21 6:46 PM, Marc Zyngier wrote:
> Even when the VM is configured with highmem=off, the highest_gpa
> field includes devices that are above the 4GiB limit.
> Similarily, nothing seem to check that the memory is within
> the limit set by the highmem=off option.
>
> This leads to failures in virt_kvm_type() on systems that have
> a crippled IPA range, as the reported IPA space is larger than
> what it should be.
>
> Instead, honor the user-specified limit to only use the devices
> at the lowest end of the spectrum, and fail if we have memory
> crossing the 4GiB limit.
>
> Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
> ---
> hw/arm/virt.c | 9 ++++++++-
> 1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/hw/arm/virt.c b/hw/arm/virt.c
> index bcf58f677d..9d2abdbd5f 100644
> --- a/hw/arm/virt.c
> +++ b/hw/arm/virt.c
> @@ -1628,6 +1628,11 @@ static void virt_set_memmap(VirtMachineState *vms)
> exit(EXIT_FAILURE);
> }
>
> + if (!vms->highmem &&
> + vms->memmap[VIRT_MEM].base + ms->maxram_size > 4 * GiB) {
> + error_report("highmem=off, but memory crosses the 4GiB limit\n");
> + exit(EXIT_FAILURE);
> + }
> /*
> * We compute the base of the high IO region depending on the
> * amount of initial and device memory. The device memory start/size
> @@ -1657,7 +1662,9 @@ static void virt_set_memmap(VirtMachineState *vms)
> vms->memmap[i].size = size;
> base += size;
> }
> - vms->highest_gpa = base - 1;
> + vms->highest_gpa = (vms->highmem ?
> + base :
> + vms->memmap[VIRT_MEM].base + ms->maxram_size) - 1;
I think I would have preferred to have
if (vms->highmem) {
for (i = VIRT_LOWMEMMAP_LAST; i < ARRAY_SIZE(extended_memmap); i++) {
hwaddr size = extended_memmap[i].size;
base = ROUND_UP(base, size);
vms->memmap[i].base = base;
vms->memmap[i].size = size;
base += size;
}
}
as it is useless to execute that code and create new memmap entries in
case of !highmem.
But nevertheless, this looks correct
Eric
> if (device_memory_size > 0) {
> ms->device_memory = g_malloc0(sizeof(*ms->device_memory));
> ms->device_memory->base = device_memory_base;
