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Re: [Qemu-devel] [PATCH v5 1/3] hw/acpi-build: Fix SRAT memory building
From: |
Igor Mammedov |
Subject: |
Re: [Qemu-devel] [PATCH v5 1/3] hw/acpi-build: Fix SRAT memory building in case of node 0 without RAM |
Date: |
Mon, 4 Sep 2017 13:11:18 +0200 |
On Mon, 4 Sep 2017 18:16:31 +0800
Dou Liyang <address@hidden> wrote:
> At 09/04/2017 05:39 PM, Igor Mammedov wrote:
> > On Thu, 31 Aug 2017 20:04:26 +0800
> > Dou Liyang <address@hidden> wrote:
> >
> >> From: Eduardo Habkost <address@hidden>
> >>
> >> Currently, Using the fisrt node without memory on the machine makes
> >> QEMU unhappy. With this example command line:
> >> ... \
> >> -m 1024M,slots=4,maxmem=32G \
> >> -numa node,nodeid=0 \
> >> -numa node,mem=1024M,nodeid=1 \
> >> -numa node,nodeid=2 \
> >> -numa node,nodeid=3 \
> >> Guest reports "No NUMA configuration found" and the NUMA topology is
> >> wrong.
> >>
> >> This is because when QEMU builds ACPI SRAT, it regards node 0 as the
> >> default node to deal with the memory hole(640K-1M). this means the
> >> node0 must have some memory(>1M), but, actually it can have no
> >> memory.
> >>
> >> Fix this problem by cut out the 640K hole in the same way the PCI
> >> 4G hole does. Also do some cleanup.
> >>
> >> Signed-off-by: Eduardo Habkost <address@hidden>
> >> Signed-off-by: Dou Liyang <address@hidden>
> >> ---
> >> hw/i386/acpi-build.c | 30 +++++++++++++++++++++++-------
> >> 1 file changed, 23 insertions(+), 7 deletions(-)
> >>
> >> diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> >> index 98dd424..48525a1 100644
> >> --- a/hw/i386/acpi-build.c
> >> +++ b/hw/i386/acpi-build.c
> >> @@ -2318,6 +2318,9 @@ build_tpm2(GArray *table_data, BIOSLinker *linker)
> >> (void *)tpm2_ptr, "TPM2", sizeof(*tpm2_ptr), 4, NULL,
> >> NULL);
> >> }
> >>
> >> +#define HOLE_640K_START (640 * 1024)
> >> +#define HOLE_640K_END (1024 * 1024)
> >> +
> >> static void
> >> build_srat(GArray *table_data, BIOSLinker *linker, MachineState *machine)
> >> {
> >> @@ -2373,17 +2376,30 @@ build_srat(GArray *table_data, BIOSLinker *linker,
> >> MachineState *machine)
> >> next_base = 0;
> >> numa_start = table_data->len;
> >>
> >> - numamem = acpi_data_push(table_data, sizeof *numamem);
> >> - build_srat_memory(numamem, 0, 640 * 1024, 0, MEM_AFFINITY_ENABLED);
> >> - next_base = 1024 * 1024;
> >> for (i = 1; i < pcms->numa_nodes + 1; ++i) {
> >> mem_base = next_base;
> >> mem_len = pcms->node_mem[i - 1];
> >> - if (i == 1) {
> >> - mem_len -= 1024 * 1024;
> >> - }
> >> next_base = mem_base + mem_len;
> >>
> >> + /* Cut out the 640K hole */
> >> + if (mem_base <= HOLE_640K_START &&
> >> + next_base > HOLE_640K_START) {
> >> + mem_len -= next_base - HOLE_640K_START;
> >> + if (mem_len > 0) {
> >> + numamem = acpi_data_push(table_data, sizeof *numamem);
> >> + build_srat_memory(numamem, mem_base, mem_len, i - 1,
> >> + MEM_AFFINITY_ENABLED);
> >> + }
> >> +
> >> + /* Check for the rare case: 640K < RAM < 1M */
> >> + if (next_base <= HOLE_640K_END) {
> >> + next_base = HOLE_640K_END;
> > Is this assignment really necessary?
> >
>
> It is necessary, because we set mem_base to next_base before setting
> next_base;
>
> But, I can refine it:
>
> MEM_AFFINITY_ENABLED);
> }
>
> + mem_base = HOLE_640K_END;
> /* Check for the rare case: 640K < RAM < 1M */
> if (next_base <= HOLE_640K_END) {
> - next_base = HOLE_640K_END;
> continue;
> }
> - mem_base = HOLE_640K_END;
> mem_len = next_base - HOLE_640K_END;
> }
>
> Is it?
I was wrong, so just leave it as it is now.
>
> Thanks,
> dou.
>
> > it seems that next_base will be set at the start of the loop.
> >
>
>
> >> + continue;
> >> + }
> >> + mem_base = HOLE_640K_END;
> >> + mem_len = next_base - HOLE_640K_END;
> >> + }
> >> +
> >> /* Cut out the ACPI_PCI hole */
> >> if (mem_base <= pcms->below_4g_mem_size &&
> >> next_base > pcms->below_4g_mem_size) {
> >> @@ -2395,7 +2411,7 @@ build_srat(GArray *table_data, BIOSLinker *linker,
> >> MachineState *machine)
> >> }
> >> mem_base = 1ULL << 32;
> >> mem_len = next_base - pcms->below_4g_mem_size;
> >> - next_base += (1ULL << 32) - pcms->below_4g_mem_size;
> >> + next_base = mem_base + mem_len;
> >> }
> >> numamem = acpi_data_push(table_data, sizeof *numamem);
> >> build_srat_memory(numamem, mem_base, mem_len, i - 1,
> >
> >
> >
> >
>
>