On 2022/01/20 21:36, Peter Maydell wrote:
From: Marc Zyngier <maz@xxxxxxxxxx>
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.
Reviewed-by: Andrew Jones <drjones@xxxxxxxxxx>
Reviewed-by: Eric Auger <eric.auger@xxxxxxxxxx>
Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
Message-id: 20220114140741.1358263-4-maz@xxxxxxxxxx
Signed-off-by: Peter Maydell <peter.maydell@xxxxxxxxxx>
---
hw/arm/virt.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index 62bdce1eb4b..3b839ba78ba 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -1670,7 +1670,7 @@ static uint64_t virt_cpu_mp_affinity(VirtMachineState *vms, int idx)
static void virt_set_memmap(VirtMachineState *vms)
{
MachineState *ms = MACHINE(vms);
- hwaddr base, device_memory_base, device_memory_size;
+ hwaddr base, device_memory_base, device_memory_size, memtop;
int i;
vms->memmap = extended_memmap;
@@ -1697,7 +1697,11 @@ static void virt_set_memmap(VirtMachineState *vms)
device_memory_size = ms->maxram_size - ms->ram_size + ms->ram_slots * GiB;
/* Base address of the high IO region */
- base = device_memory_base + ROUND_UP(device_memory_size, GiB);
+ memtop = base = device_memory_base + ROUND_UP(device_memory_size, GiB);
+ if (!vms->highmem && memtop > 4 * GiB) {
+ error_report("highmem=off, but memory crosses the 4GiB limit\n");
+ exit(EXIT_FAILURE);
+ }
if (base < device_memory_base) {
error_report("maxmem/slots too huge");
exit(EXIT_FAILURE);
@@ -1714,7 +1718,7 @@ 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 : memtop) - 1;
if (device_memory_size > 0) {
ms->device_memory = g_malloc0(sizeof(*ms->device_memory));
ms->device_memory->base = device_memory_base;
Hi,
This breaks in a case where highmem is disabled but can have more than 4
GiB of RAM. M1 (Apple Silicon) actually can have 36-bit PA with HVF,
which is not enough for highmem MMIO but is enough to contain 32 GiB of RAM.
Where the magic number of 4 GiB / 32-bit came from? I also don't quite
understand what failures virt_kvm_type() had.
Regards,
Akihiko Odaki
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