[PATCH v2 kvmtool 12/12] arm64: Allow the user to specify the RAM base address
Alexandru Elisei
alexandru.elisei at arm.com
Mon May 23 10:20:32 PDT 2022
Hi,
Pushed an updated branch [1] with the fix below and another fix for
checking when memory exceeds 4GB on aarch32. Minimally tested while I put
my testing scripts in order.
[1] https://gitlab.arm.com/linux-arm/kvmtool-ae/-/tree/arm-allow-the-user-to-define-ram-address-v3-wip1
Thanks,
Alex
On Mon, May 23, 2022 at 09:55:30AM +0100, Alexandru Elisei wrote:
> Hi Andre,
>
> Thank you for having a look!
>
> On Fri, May 20, 2022 at 06:20:15PM +0100, Andre Przywara wrote:
> > On Mon, 16 May 2022 16:55:26 +0100
> > Alexandru Elisei <alexandru.elisei at arm.com> wrote:
> >
> > Hi,
> >
> > > Allow the user to specify the RAM base address by using -m/--mem size at addr
> > > command line argument. The base address must be above 2GB, as to not
> > > overlap with the MMIO I/O region.
> >
> > Just started to play with this, in general the series looks good to me on
> > a first glance. I will review in anger next week.
> > Meanwhile: when you start kvmtool without explicitly specifying a ram size
> > on the command line, the code misses to initialise cfg.ram_addr, so it
> > stays at 0 and kvmtool reports:
> > Fatal: RAM address is below 2GB
> > One possible fix would be to initialise this in get_ram_size() to
> > kvm__arch_default_ram_address(), I guess, but you might find a better solution.
>
> This is indeed an issue. I usually specify the number of vcpus and the
> memory size when I create a VM, and I overlooked what happens with the
> default values. I will incorporate this scenario into my testing.
>
> Will send an updated series with the bug fixed as soon as possible. In the
> meantime, this fixed the issue for me and I plan to incorporate it into the
> series after more testing:
>
> diff --git a/builtin-run.c b/builtin-run.c
> index 26e6e9974009..36a255bc14f9 100644
> --- a/builtin-run.c
> +++ b/builtin-run.c
> @@ -137,7 +137,6 @@ static int mem_parser(const struct option *opt, const char *arg, int unset)
> if (kvm->cfg.ram_size == 0)
> die("Invalid RAM size: %s", arg);
>
> - kvm->cfg.ram_addr = kvm__arch_default_ram_address();
> if (kvm__arch_has_cfg_ram_address() && *next == '@') {
> next++;
> if (*next == '\0')
> @@ -622,6 +621,7 @@ static struct kvm *kvm_cmd_run_init(int argc, const char **argv)
>
> nr_online_cpus = sysconf(_SC_NPROCESSORS_ONLN);
> kvm->cfg.custom_rootfs_name = "default";
> + kvm->cfg.ram_addr = kvm__arch_default_ram_address();
>
> while (argc != 0) {
> BUILD_OPTIONS(options, &kvm->cfg, kvm);
>
> Thanks,
> Alex
>
> >
> > Cheers,
> > Andre
> >
> > >
> > > Signed-off-by: Alexandru Elisei <alexandru.elisei at arm.com>
> > > ---
> > > arm/aarch64/include/kvm/kvm-arch.h | 2 ++
> > > arm/aarch64/kvm.c | 5 ++++-
> > > arm/kvm.c | 7 +++++--
> > > builtin-run.c | 29 +++++++++++++++++++++++++----
> > > include/kvm/kvm-config.h | 1 +
> > > include/kvm/kvm.h | 12 ++++++++++++
> > > 6 files changed, 49 insertions(+), 7 deletions(-)
> > >
> > > diff --git a/arm/aarch64/include/kvm/kvm-arch.h b/arm/aarch64/include/kvm/kvm-arch.h
> > > index ff857ca6e7b4..02d09a413831 100644
> > > --- a/arm/aarch64/include/kvm/kvm-arch.h
> > > +++ b/arm/aarch64/include/kvm/kvm-arch.h
> > > @@ -10,6 +10,8 @@ void kvm__arch_enable_mte(struct kvm *kvm);
> > >
> > > #define MAX_PAGE_SIZE SZ_64K
> > >
> > > +#define ARCH_HAS_CFG_RAM_ADDRESS 1
> > > +
> > > #include "arm-common/kvm-arch.h"
> > >
> > > #endif /* KVM__KVM_ARCH_H */
> > > diff --git a/arm/aarch64/kvm.c b/arm/aarch64/kvm.c
> > > index af8e7eae0da2..14ffae9e39dc 100644
> > > --- a/arm/aarch64/kvm.c
> > > +++ b/arm/aarch64/kvm.c
> > > @@ -44,6 +44,9 @@ void kvm__arch_validate_cfg(struct kvm *kvm)
> > > die("RAM size 0x%llx exceeds maximum allowed 0x%llx",
> > > kvm->cfg.ram_size, ARM_LOMAP_MAX_MEMORY);
> > > }
> > > +
> > > + if (kvm->cfg.ram_addr < ARM_MEMORY_AREA)
> > > + die("RAM address is below %luGB", ARM_MEMORY_AREA >> 30);
> > > }
> > >
> > > u64 kvm__arch_default_ram_address(void)
> > > @@ -117,7 +120,7 @@ int kvm__get_vm_type(struct kvm *kvm)
> > > return 0;
> > >
> > > /* Otherwise, compute the minimal required IPA size */
> > > - max_ipa = ARM_MEMORY_AREA + kvm->cfg.ram_size - 1;
> > > + max_ipa = kvm->cfg.ram_addr + kvm->cfg.ram_size - 1;
> > > ipa_bits = max(32, fls_long(max_ipa));
> > > pr_debug("max_ipa %lx ipa_bits %d max_ipa_bits %d",
> > > max_ipa, ipa_bits, max_ipa_bits);
> > > diff --git a/arm/kvm.c b/arm/kvm.c
> > > index abcccfabf59e..d51cc15d8b1c 100644
> > > --- a/arm/kvm.c
> > > +++ b/arm/kvm.c
> > > @@ -55,7 +55,7 @@ void kvm__init_ram(struct kvm *kvm)
> > > madvise(kvm->arch.ram_alloc_start, kvm->arch.ram_alloc_size,
> > > MADV_HUGEPAGE);
> > >
> > > - phys_start = ARM_MEMORY_AREA;
> > > + phys_start = kvm->cfg.ram_addr;
> > > phys_size = kvm->ram_size;
> > > host_mem = kvm->ram_start;
> > >
> > > @@ -65,6 +65,9 @@ void kvm__init_ram(struct kvm *kvm)
> > > "address 0x%llx [err %d]", phys_size, phys_start, err);
> > >
> > > kvm->arch.memory_guest_start = phys_start;
> > > +
> > > + pr_debug("RAM created at 0x%llx - 0x%llx",
> > > + phys_start, phys_start + phys_size - 1);
> > > }
> > >
> > > void kvm__arch_delete_ram(struct kvm *kvm)
> > > @@ -201,7 +204,7 @@ bool kvm__load_firmware(struct kvm *kvm, const char *firmware_filename)
> > >
> > > /* For default firmware address, lets load it at the begining of RAM */
> > > if (fw_addr == 0)
> > > - fw_addr = ARM_MEMORY_AREA;
> > > + fw_addr = kvm->arch.memory_guest_start;
> > >
> > > if (!validate_fw_addr(kvm, fw_addr))
> > > die("Bad firmware destination: 0x%016llx", fw_addr);
> > > diff --git a/builtin-run.c b/builtin-run.c
> > > index 57c58be55159..26e6e9974009 100644
> > > --- a/builtin-run.c
> > > +++ b/builtin-run.c
> > > @@ -131,12 +131,22 @@ static u64 parse_mem_option(const char *nptr, char **next)
> > > static int mem_parser(const struct option *opt, const char *arg, int unset)
> > > {
> > > struct kvm *kvm = opt->ptr;
> > > - char *next;
> > > + char *next, *nptr;
> > >
> > > kvm->cfg.ram_size = parse_mem_option(arg, &next);
> > > if (kvm->cfg.ram_size == 0)
> > > die("Invalid RAM size: %s", arg);
> > >
> > > + kvm->cfg.ram_addr = kvm__arch_default_ram_address();
> > > + if (kvm__arch_has_cfg_ram_address() && *next == '@') {
> > > + next++;
> > > + if (*next == '\0')
> > > + die("Missing memory address: %s", arg);
> > > +
> > > + nptr = next;
> > > + kvm->cfg.ram_addr = parse_mem_option(nptr, &next);
> > > + }
> > > +
> > > if (*next != '\0')
> > > die("Invalid memory specifier: %s", arg);
> > >
> > > @@ -147,15 +157,26 @@ static int mem_parser(const struct option *opt, const char *arg, int unset)
> > > #define OPT_ARCH_RUN(...)
> > > #endif
> > >
> > > +#ifdef ARCH_HAS_CFG_RAM_ADDRESS
> > > +#define MEM_OPT_HELP_SHORT "size[BKMGTP][@addr[BKMGTP]]"
> > > +#define MEM_OPT_HELP_LONG \
> > > + "Virtual machine memory size and optional base address, both" \
> > > + " measured by default in megabytes (M)"
> > > +#else
> > > +#define MEM_OPT_HELP_SHORT "size[BKMGTP]"
> > > +#define MEM_OPT_HELP_LONG \
> > > + "Virtual machine memory size, by default measured in" \
> > > + " in megabytes (M)"
> > > +#endif
> > > +
> > > #define BUILD_OPTIONS(name, cfg, kvm) \
> > > struct option name[] = { \
> > > OPT_GROUP("Basic options:"), \
> > > OPT_STRING('\0', "name", &(cfg)->guest_name, "guest name", \
> > > "A name for the guest"), \
> > > OPT_INTEGER('c', "cpus", &(cfg)->nrcpus, "Number of CPUs"), \
> > > - OPT_CALLBACK('m', "mem", NULL, "size[BKMGTP]", \
> > > - "Virtual machine memory size, by default measured" \
> > > - " in megabytes (M)", mem_parser, kvm), \
> > > + OPT_CALLBACK('m', "mem", NULL, MEM_OPT_HELP_SHORT, \
> > > + MEM_OPT_HELP_LONG, mem_parser, kvm), \
> > > OPT_CALLBACK('d', "disk", kvm, "image or rootfs_dir", "Disk " \
> > > " image or rootfs directory", img_name_parser, \
> > > kvm), \
> > > diff --git a/include/kvm/kvm-config.h b/include/kvm/kvm-config.h
> > > index 31bc89520d52..45fe1caaebce 100644
> > > --- a/include/kvm/kvm-config.h
> > > +++ b/include/kvm/kvm-config.h
> > > @@ -23,6 +23,7 @@ struct kvm_config {
> > > struct kvm_config_arch arch;
> > > struct disk_image_params disk_image[MAX_DISK_IMAGES];
> > > struct vfio_device_params *vfio_devices;
> > > + u64 ram_addr; /* Guest memory physical base address, in bytes */
> > > u64 ram_size; /* Guest memory size, in bytes */
> > > u8 num_net_devices;
> > > u8 num_vfio_devices;
> > > diff --git a/include/kvm/kvm.h b/include/kvm/kvm.h
> > > index 360430b78b1e..eb23e2f77310 100644
> > > --- a/include/kvm/kvm.h
> > > +++ b/include/kvm/kvm.h
> > > @@ -197,6 +197,18 @@ int kvm__arch_free_firmware(struct kvm *kvm);
> > > bool kvm__arch_cpu_supports_vm(void);
> > > void kvm__arch_read_term(struct kvm *kvm);
> > >
> > > +#ifdef ARCH_HAS_CFG_RAM_ADDRESS
> > > +static inline bool kvm__arch_has_cfg_ram_address(void)
> > > +{
> > > + return true;
> > > +}
> > > +#else
> > > +static inline bool kvm__arch_has_cfg_ram_address(void)
> > > +{
> > > + return false;
> > > +}
> > > +#endif
> > > +
> > > void *guest_flat_to_host(struct kvm *kvm, u64 offset);
> > > u64 host_to_guest_flat(struct kvm *kvm, void *ptr);
> > >
> >
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