Hi Marc,
On 1/7/22 5:33 PM, Marc Zyngier wrote:
> The highmem attribute is nothing but another way to express the
> PA range of a VM. To support HW that has a smaller PA range then
> what QEMU assumes, pass this PA range to the virt_set_memmap()
> function, allowing it to correctly exclude highmem devices
> if they are outside of the PA range.
>
> Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
> ---
> hw/arm/virt.c | 53 ++++++++++++++++++++++++++++++++++++++++++++-------
> 1 file changed, 46 insertions(+), 7 deletions(-)
>
> diff --git a/hw/arm/virt.c b/hw/arm/virt.c
> index 57c55e8a37..db4b0636e1 100644
> --- a/hw/arm/virt.c
> +++ b/hw/arm/virt.c
> @@ -1660,7 +1660,7 @@ static uint64_t virt_cpu_mp_affinity(VirtMachineState *vms, int idx)
> return arm_cpu_mp_affinity(idx, clustersz);
> }
>
> -static void virt_set_memmap(VirtMachineState *vms)
> +static void virt_set_memmap(VirtMachineState *vms, int pa_bits)
> {
> MachineState *ms = MACHINE(vms);
> hwaddr base, device_memory_base, device_memory_size, memtop;
> @@ -1678,6 +1678,13 @@ static void virt_set_memmap(VirtMachineState *vms)
> exit(EXIT_FAILURE);
> }
>
> + /*
> + * !highmem is exactly the same as limiting the PA space to 32bit,
> + * irrespective of the underlying capabilities of the HW.
> + */
> + if (!vms->highmem)
> + pa_bits = 32;
you need {} according to the QEMU coding style. Welcome to a new shiny
world :-)
> +
> /*
> * We compute the base of the high IO region depending on the
> * amount of initial and device memory. The device memory start/size
> @@ -1691,8 +1698,9 @@ static void virt_set_memmap(VirtMachineState *vms)
>
> /* Base address of the high IO region */
> 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");
> + if (memtop > BIT_ULL(pa_bits)) {
> + error_report("Addressing limited to %d bits, but memory exceeds it by %llu bytes\n",
> + pa_bits, memtop - BIT_ULL(pa_bits));
> exit(EXIT_FAILURE);
> }
> if (base < device_memory_base) {
> @@ -1711,7 +1719,13 @@ static void virt_set_memmap(VirtMachineState *vms)
> vms->memmap[i].size = size;
> base += size;
> }
> - vms->highest_gpa = (vms->highmem ? base : memtop) - 1;
> +
> + /*
> + * If base fits within pa_bits, all good. If it doesn't, limit it
> + * to the end of RAM, which is guaranteed to fit within pa_bits.
> + */
> + vms->highest_gpa = (base <= BIT_ULL(pa_bits) ? base : memtop) - 1;
> +
> if (device_memory_size > 0) {
> ms->device_memory = g_malloc0(sizeof(*ms->device_memory));
> ms->device_memory->base = device_memory_base;
> @@ -1902,12 +1916,38 @@ static void machvirt_init(MachineState *machine)
> unsigned int smp_cpus = machine->smp.cpus;
> unsigned int max_cpus = machine->smp.max_cpus;
Move the cpu_type check before?
if (!cpu_type_valid(machine->cpu_type)) {
error_report("mach-virt: CPU type %s not supported",
machine->cpu_type);
exit(1);
}
>
> + possible_cpus = mc->possible_cpu_arch_ids(machine);
> +
> /*
> * In accelerated mode, the memory map is computed earlier in kvm_type()
> * to create a VM with the right number of IPA bits.
> */
> if (!vms->memmap) {
> - virt_set_memmap(vms);
> + Object *cpuobj;
> + ARMCPU *armcpu;
> + int pa_bits;
> +
> + /*
> + * Instanciate a temporary CPU object to find out about what
> + * we are about to deal with. Once this is done, get rid of
> + * the object.
> + */
> + cpuobj = object_new(possible_cpus->cpus[0].type);
> + armcpu = ARM_CPU(cpuobj);
> +
> + if (object_property_get_bool(cpuobj, "aarch64", NULL)) {
> + pa_bits = arm_pamax(armcpu);
> + } else if (arm_feature(&armcpu->env, ARM_FEATURE_LPAE)) {
> + /* v7 with LPAE */
> + pa_bits = 40;
> + } else {
> + /* Anything else */
> + pa_bits = 32;
> + }
> +
> + object_unref(cpuobj);
> +
> + virt_set_memmap(vms, pa_bits);
> }
>
> /* We can probe only here because during property set
> @@ -1989,7 +2029,6 @@ static void machvirt_init(MachineState *machine)
>
> create_fdt(vms);
>
> - possible_cpus = mc->possible_cpu_arch_ids(machine);
> assert(possible_cpus->len == max_cpus);
> for (n = 0; n < possible_cpus->len; n++) {
> Object *cpuobj;
> @@ -2646,7 +2685,7 @@ static int virt_kvm_type(MachineState *ms, const char *type_str)
> max_vm_pa_size = kvm_arm_get_max_vm_ipa_size(ms, &fixed_ipa);
>
> /* we freeze the memory map to compute the highest gpa */
> - virt_set_memmap(vms);
> + virt_set_memmap(vms, max_vm_pa_size);
>
> requested_pa_size = 64 - clz64(vms->highest_gpa);
>
Thanks
Eric
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