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Re: [Qemu-devel] [PATCH for-4.2 v5 1/2] kvm: s390: split too big memory
From: |
Cornelia Huck |
Subject: |
Re: [Qemu-devel] [PATCH for-4.2 v5 1/2] kvm: s390: split too big memory section on several memslots |
Date: |
Tue, 20 Aug 2019 18:07:27 +0200 |
On Wed, 7 Aug 2019 11:32:41 -0400
Igor Mammedov <address@hidden> wrote:
> Max memslot size supported by kvm on s390 is 8Tb,
> move logic of splitting RAM in chunks upto 8T to KVM code.
>
> This way it will hide KVM specific restrictions in KVM code
> and won't affect baord level design decisions. Which would allow
> us to avoid misusing memory_region_allocate_system_memory() API
> and eventually use a single hostmem backend for guest RAM.
>
> Signed-off-by: Igor Mammedov <address@hidden>
> ---
> v5:
> * move computation 'size -= slot_size' inside of loop body
> (David Hildenbrand <address@hidden>)
> v4:
> * fix compilation issue
> (Christian Borntraeger <address@hidden>)
> * advance HVA along with GPA in kvm_set_phys_mem()
> (Christian Borntraeger <address@hidden>)
>
> patch prepares only KVM side for switching to single RAM memory region
> another patch will take care of dropping manual RAM partitioning in
> s390 code.
I may have lost track a bit -- what is the status of this patch (and
the series)?
> ---
> include/sysemu/kvm_int.h | 1 +
> accel/kvm/kvm-all.c | 82 ++++++++++++++++++++++++--------------
> hw/s390x/s390-virtio-ccw.c | 9 -----
> target/s390x/kvm.c | 12 ++++++
> 4 files changed, 64 insertions(+), 40 deletions(-)
>
> diff --git a/include/sysemu/kvm_int.h b/include/sysemu/kvm_int.h
> index 31df465fdc..7f7520bce2 100644
> --- a/include/sysemu/kvm_int.h
> +++ b/include/sysemu/kvm_int.h
> @@ -41,4 +41,5 @@ typedef struct KVMMemoryListener {
> void kvm_memory_listener_register(KVMState *s, KVMMemoryListener *kml,
> AddressSpace *as, int as_id);
>
> +void kvm_set_max_memslot_size(hwaddr max_slot_size);
> #endif
> diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
> index f450f25295..8153556335 100644
> --- a/accel/kvm/kvm-all.c
> +++ b/accel/kvm/kvm-all.c
> @@ -138,6 +138,7 @@ bool kvm_direct_msi_allowed;
> bool kvm_ioeventfd_any_length_allowed;
> bool kvm_msi_use_devid;
> static bool kvm_immediate_exit;
> +static hwaddr kvm_max_slot_size = ~0;
>
> static const KVMCapabilityInfo kvm_required_capabilites[] = {
> KVM_CAP_INFO(USER_MEMORY),
> @@ -951,6 +952,14 @@ kvm_check_extension_list(KVMState *s, const
> KVMCapabilityInfo *list)
> return NULL;
> }
>
> +void kvm_set_max_memslot_size(hwaddr max_slot_size)
> +{
> + g_assert(
> + ROUND_UP(max_slot_size, qemu_real_host_page_size) == max_slot_size
> + );
> + kvm_max_slot_size = max_slot_size;
> +}
> +
> static void kvm_set_phys_mem(KVMMemoryListener *kml,
> MemoryRegionSection *section, bool add)
> {
> @@ -958,7 +967,7 @@ static void kvm_set_phys_mem(KVMMemoryListener *kml,
> int err;
> MemoryRegion *mr = section->mr;
> bool writeable = !mr->readonly && !mr->rom_device;
> - hwaddr start_addr, size;
> + hwaddr start_addr, size, slot_size;
> void *ram;
>
> if (!memory_region_is_ram(mr)) {
> @@ -983,41 +992,52 @@ static void kvm_set_phys_mem(KVMMemoryListener *kml,
> kvm_slots_lock(kml);
>
> if (!add) {
> - mem = kvm_lookup_matching_slot(kml, start_addr, size);
> - if (!mem) {
> - goto out;
> - }
> - if (mem->flags & KVM_MEM_LOG_DIRTY_PAGES) {
> - kvm_physical_sync_dirty_bitmap(kml, section);
> - }
> + do {
> + slot_size = kvm_max_slot_size < size ? kvm_max_slot_size : size;
> + mem = kvm_lookup_matching_slot(kml, start_addr, slot_size);
> + if (!mem) {
> + goto out;
> + }
> + if (mem->flags & KVM_MEM_LOG_DIRTY_PAGES) {
> + kvm_physical_sync_dirty_bitmap(kml, section);
> + }
>
> - /* unregister the slot */
> - g_free(mem->dirty_bmap);
> - mem->dirty_bmap = NULL;
> - mem->memory_size = 0;
> - mem->flags = 0;
> - err = kvm_set_user_memory_region(kml, mem, false);
> - if (err) {
> - fprintf(stderr, "%s: error unregistering slot: %s\n",
> - __func__, strerror(-err));
> - abort();
> - }
> + /* unregister the slot */
> + g_free(mem->dirty_bmap);
> + mem->dirty_bmap = NULL;
> + mem->memory_size = 0;
> + mem->flags = 0;
> + err = kvm_set_user_memory_region(kml, mem, false);
> + if (err) {
> + fprintf(stderr, "%s: error unregistering slot: %s\n",
> + __func__, strerror(-err));
> + abort();
> + }
> + start_addr += slot_size;
> + size -= slot_size;
> + } while (size);
> goto out;
> }
>
> /* register the new slot */
> - mem = kvm_alloc_slot(kml);
> - mem->memory_size = size;
> - mem->start_addr = start_addr;
> - mem->ram = ram;
> - mem->flags = kvm_mem_flags(mr);
> -
> - err = kvm_set_user_memory_region(kml, mem, true);
> - if (err) {
> - fprintf(stderr, "%s: error registering slot: %s\n", __func__,
> - strerror(-err));
> - abort();
> - }
> + do {
> + slot_size = kvm_max_slot_size < size ? kvm_max_slot_size : size;
> + mem = kvm_alloc_slot(kml);
> + mem->memory_size = slot_size;
> + mem->start_addr = start_addr;
> + mem->ram = ram;
> + mem->flags = kvm_mem_flags(mr);
> +
> + err = kvm_set_user_memory_region(kml, mem, true);
> + if (err) {
> + fprintf(stderr, "%s: error registering slot: %s\n", __func__,
> + strerror(-err));
> + abort();
> + }
> + start_addr += slot_size;
> + ram += slot_size;
> + size -= slot_size;
> + } while (size);
>
> out:
> kvm_slots_unlock(kml);
> diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
> index 5b6a9a4e55..0c03ffb7c7 100644
> --- a/hw/s390x/s390-virtio-ccw.c
> +++ b/hw/s390x/s390-virtio-ccw.c
> @@ -151,15 +151,6 @@ static void virtio_ccw_register_hcalls(void)
> virtio_ccw_hcall_early_printk);
> }
>
> -/*
> - * KVM does only support memory slots up to KVM_MEM_MAX_NR_PAGES pages
> - * as the dirty bitmap must be managed by bitops that take an int as
> - * position indicator. If we have a guest beyond that we will split off
> - * new subregions. The split must happen on a segment boundary (1MB).
> - */
> -#define KVM_MEM_MAX_NR_PAGES ((1ULL << 31) - 1)
> -#define SEG_MSK (~0xfffffULL)
> -#define KVM_SLOT_MAX_BYTES ((KVM_MEM_MAX_NR_PAGES * TARGET_PAGE_SIZE) &
> SEG_MSK)
> static void s390_memory_init(ram_addr_t mem_size)
> {
> MemoryRegion *sysmem = get_system_memory();
> diff --git a/target/s390x/kvm.c b/target/s390x/kvm.c
> index 6e814c230b..6b1428a760 100644
> --- a/target/s390x/kvm.c
> +++ b/target/s390x/kvm.c
> @@ -28,6 +28,7 @@
> #include "cpu.h"
> #include "internal.h"
> #include "kvm_s390x.h"
> +#include "sysemu/kvm_int.h"
> #include "qapi/error.h"
> #include "qemu/error-report.h"
> #include "qemu/timer.h"
> @@ -122,6 +123,16 @@
> #define VCPU_IRQ_BUF_SIZE(max_cpus) (sizeof(struct kvm_s390_irq) * \
> (max_cpus + NR_LOCAL_IRQS))
>
> +/*
> + * KVM does only support memory slots up to KVM_MEM_MAX_NR_PAGES pages
> + * as the dirty bitmap must be managed by bitops that take an int as
> + * position indicator. If we have a guest beyond that we will split off
> + * new subregions. The split must happen on a segment boundary (1MB).
> + */
> +#define KVM_MEM_MAX_NR_PAGES ((1ULL << 31) - 1)
> +#define SEG_MSK (~0xfffffULL)
> +#define KVM_SLOT_MAX_BYTES ((KVM_MEM_MAX_NR_PAGES * TARGET_PAGE_SIZE) &
> SEG_MSK)
> +
> static CPUWatchpoint hw_watchpoint;
> /*
> * We don't use a list because this structure is also used to transmit the
> @@ -347,6 +358,7 @@ int kvm_arch_init(MachineState *ms, KVMState *s)
> */
> /* kvm_vm_enable_cap(s, KVM_CAP_S390_AIS, 0); */
>
> + kvm_set_max_memslot_size(KVM_SLOT_MAX_BYTES);
> return 0;
> }
>
- [Qemu-devel] [PATCH for-4.2 v4 0/2] s390: stop abusing memory_region_allocate_system_memory(), Igor Mammedov, 2019/08/06
- [Qemu-devel] [PATCH for-4.2 v4 1/2] kvm: s390: split too big memory section on several memslots, Igor Mammedov, 2019/08/06
- [Qemu-devel] [PATCH for-4.2 v5 1/2] kvm: s390: split too big memory section on several memslots, Igor Mammedov, 2019/08/07
- Re: [Qemu-devel] [PATCH for-4.2 v5 1/2] kvm: s390: split too big memory section on several memslots,
Cornelia Huck <=
- Re: [Qemu-devel] [PATCH for-4.2 v5 1/2] kvm: s390: split too big memory section on several memslots, Igor Mammedov, 2019/08/27
- Re: [Qemu-devel] [PATCH for-4.2 v5 1/2] kvm: s390: split too big memory section on several memslots, Christian Borntraeger, 2019/08/29
- Re: [Qemu-devel] [PATCH for-4.2 v5 1/2] kvm: s390: split too big memory section on several memslots, Igor Mammedov, 2019/08/29
- Re: [Qemu-devel] [qemu-s390x] [PATCH for-4.2 v5 1/2] kvm: s390: split too big memory section on several memslots, Christian Borntraeger, 2019/08/29
- Re: [Qemu-devel] [qemu-s390x] [PATCH for-4.2 v5 1/2] kvm: s390: split too big memory section on several memslots, Igor Mammedov, 2019/08/29
- Re: [Qemu-devel] [qemu-s390x] [PATCH for-4.2 v5 1/2] kvm: s390: split too big memory section on several memslots, Christian Borntraeger, 2019/08/29
- Re: [Qemu-devel] [qemu-s390x] [PATCH for-4.2 v5 1/2] kvm: s390: split too big memory section on several memslots, Igor Mammedov, 2019/08/30
- Re: [Qemu-devel] [qemu-s390x] [PATCH for-4.2 v5 1/2] kvm: s390: split too big memory section on several memslots, Christian Borntraeger, 2019/08/30
[Qemu-devel] [PATCH for-4.2 v4 2/2] s390: do not call memory_region_allocate_system_memory() multiple times, Igor Mammedov, 2019/08/06