* Asias He <asias.hejun@xxxxxxxxx> wrote:
> On 05/11/2011 11:17 PM, levinsasha928@xxxxxxxxx wrote:
> > From: Sasha Levin <levinsasha928@xxxxxxxxx>
> >
> > e820 is expected to leave a memory gap within the low 32
> > bits of RAM space. From the documentation of e820_setup_gap():
> > /*
> > * Search for the biggest gap in the low 32 bits of the e820
> > * memory space. We pass this space to PCI to assign MMIO resources
> > * for hotplug or unconfigured devices in.
> > * Hopefully the BIOS let enough space left.
> > */
> >
> > Not leaving such gap causes errors and hangs during the boot
> > process.
> >
> > This patch adds a memory gap between 0xe0000000 and 0x100000000
> > when using more than 0xe0000000 bytes for guest RAM.
> >
> > This patch updates the e820 table, slot allocations
> > used for KVM_SET_USER_MEMORY_REGION.
> >
> > Changes in V2:
> > - Allocate RAM with the gap to avoid altering the translation code.
> > - New patch description.
> >
> > Changes in V3:
> > - Remove unnecessary casts.
> >
> > Changes in V4:
> > - Rewrite kvm__init_ram().
> > - Document the 64bit gap within the code.
> >
> > Signed-off-by: Sasha Levin <levinsasha928@xxxxxxxxx>
> > ---
> > tools/kvm/bios.c | 27 ++++++++++++----
> > tools/kvm/include/kvm/e820.h | 2 +-
> > tools/kvm/include/kvm/kvm.h | 2 +
> > tools/kvm/kvm.c | 66 +++++++++++++++++++++++++++++++++++++----
> > 4 files changed, 82 insertions(+), 15 deletions(-)
> >
> > diff --git a/tools/kvm/bios.c b/tools/kvm/bios.c
> > index 2199c0c..3cd9b24 100644
> > --- a/tools/kvm/bios.c
> > +++ b/tools/kvm/bios.c
> > @@ -61,8 +61,6 @@ static void e820_setup(struct kvm *kvm)
> > size = guest_flat_to_host(kvm, E820_MAP_SIZE);
> > mem_map = guest_flat_to_host(kvm, E820_MAP_START);
> >
> > - *size = E820_MEM_AREAS;
> > -
> > mem_map[i++] = (struct e820_entry) {
> > .addr = REAL_MODE_IVT_BEGIN,
> > .size = EBDA_START - REAL_MODE_IVT_BEGIN,
> > @@ -78,13 +76,28 @@ static void e820_setup(struct kvm *kvm)
> > .size = MB_BIOS_END - MB_BIOS_BEGIN,
> > .type = E820_MEM_RESERVED,
> > };
> > - mem_map[i++] = (struct e820_entry) {
> > - .addr = BZ_KERNEL_START,
> > - .size = kvm->ram_size - BZ_KERNEL_START,
> > - .type = E820_MEM_USABLE,
> > - };
> > + if (kvm->ram_size < KVM_32BIT_GAP_START) {
> > + mem_map[i++] = (struct e820_entry) {
> > + .addr = BZ_KERNEL_START,
> > + .size = kvm->ram_size - BZ_KERNEL_START,
> > + .type = E820_MEM_USABLE,
> > + };
> > + } else {
> > + mem_map[i++] = (struct e820_entry) {
> > + .addr = BZ_KERNEL_START,
> > + .size = KVM_32BIT_GAP_START - BZ_KERNEL_START,
> > + .type = E820_MEM_USABLE,
> > + };
> > + mem_map[i++] = (struct e820_entry) {
> > + .addr = 0x100000000ULL,
> > + .size = kvm->ram_size - KVM_32BIT_GAP_START,
> > + .type = E820_MEM_USABLE,
> > + };
> > + }
> >
> > BUILD_BUG_ON(i > E820_MEM_AREAS);
> > +
> > + *size = i;
> > }
> >
> > /**
> > diff --git a/tools/kvm/include/kvm/e820.h b/tools/kvm/include/kvm/e820.h
> > index 252ae1f..e0f5f2a 100644
> > --- a/tools/kvm/include/kvm/e820.h
> > +++ b/tools/kvm/include/kvm/e820.h
> > @@ -8,7 +8,7 @@
> > #define E820_MEM_USABLE 1
> > #define E820_MEM_RESERVED 2
> >
> > -#define E820_MEM_AREAS 4
> > +#define E820_MEM_AREAS 5
> >
> > struct e820_entry {
> > u64 addr; /* start of memory segment */
> > diff --git a/tools/kvm/include/kvm/kvm.h b/tools/kvm/include/kvm/kvm.h
> > index 3dab78d..5e2e64c 100644
> > --- a/tools/kvm/include/kvm/kvm.h
> > +++ b/tools/kvm/include/kvm/kvm.h
> > @@ -8,6 +8,8 @@
> > #include <time.h>
> >
> > #define KVM_NR_CPUS (255)
> > +#define KVM_32BIT_GAP_SIZE (512 << 20)
> > +#define KVM_32BIT_GAP_START ((1ULL << 32) - KVM_32BIT_GAP_SIZE)
> >
> > struct kvm {
> > int sys_fd; /* For system ioctls(), i.e. /dev/kvm */
> > diff --git a/tools/kvm/kvm.c b/tools/kvm/kvm.c
> > index 65793f2..a3d3dd8 100644
> > --- a/tools/kvm/kvm.c
> > +++ b/tools/kvm/kvm.c
> > @@ -153,23 +153,64 @@ static bool kvm__cpu_supports_vm(void)
> > return regs.ecx & (1 << feature);
> > }
> >
> > -void kvm__init_ram(struct kvm *self)
> > +static void kvm_register_mem_slot(struct kvm *kvm, u32 slot, u64 guest_phys, u64 size, void *userspace_addr)
> > {
> > struct kvm_userspace_memory_region mem;
> > int ret;
> >
> > mem = (struct kvm_userspace_memory_region) {
> > - .slot = 0,
> > - .guest_phys_addr = 0x0UL,
> > - .memory_size = self->ram_size,
> > - .userspace_addr = (unsigned long) self->ram_start,
> > + .slot = slot,
> > + .guest_phys_addr = guest_phys,
> > + .memory_size = size,
> > + .userspace_addr = (u64)userspace_addr,
>
>
> I am seeing:
>
> CC kvm.o
> kvm.c: In function âkvm_register_mem_slotâ:
> kvm.c:165:22: error: cast from pointer to integer of different size
> [-Werror=pointer-to-int-cast]
> cc1: all warnings being treated as errors
>
> make: *** [kvm.o] Error 1
>
> with this patch on 32-bit box.
it's useful if you report the 'gcc -v' output for compiler warnings - so that
we can after some time have a mental picture of which GCC versions produce
spurious warnings.
Btw,. it would also be useful to add a 'make WERROR=0' option - that way
warnings that trigger only on some GCC versions can be skipped during the build
while they will still be reported to us because the default 'make' fails.
[ If you add that then please also send such a patch against tools/perf/ :-) ]
Thanks,
Ingo
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