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@xxxxxxx> wrote:
>
> Hi,
>
> > Allow the user to specify the RAM base address by using -m/--mem size@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@xxxxxxx>
> > ---
> > 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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