[PATCH 2/3] hw/arm/virt: Honor highmem setting when computing highest_gpa

[Marc Zyngier]

Even when the VM is configured with highmem=off, the highest_gpa
field includes devices that are above the 4GiB limit, which is
what highmem=off is supposed to enforce. 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.

Note that this doesn't affect memory, which is still allowed to
go beyond 4GiB with highmem=on configurations.

Cc: Andrew Jones <drjones@redhat.com>
Cc: Eric Auger <eric.auger@redhat.com>
Cc: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 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 81eda46b0b..bc189e30b8 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -1598,7 +1598,7 @@ 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, ceiling;
     int i;
 
     vms->memmap = extended_memmap;
@@ -1625,7 +1625,7 @@ 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);
+    ceiling = base = device_memory_base + ROUND_UP(device_memory_size, GiB);
     if (base < device_memory_base) {
         error_report("maxmem/slots too huge");
         exit(EXIT_FAILURE);
@@ -1642,7 +1642,11 @@ static void virt_set_memmap(VirtMachineState *vms)
         vms->memmap[i].size = size;
         base += size;
     }
-    vms->highest_gpa = base - 1;
+    if (vms->highmem) {
+           /* If we have highmem, move the IPA limit to the top */
+           ceiling = base;
+    }
+    vms->highest_gpa = ceiling - 1;
     if (device_memory_size > 0) {
         ms->device_memory = g_malloc0(sizeof(*ms->device_memory));
         ms->device_memory->base = device_memory_base;
-- 
2.30.2