Hello,
On 12/25/19 3:00 AM, Anup Patel wrote:
> This patch implements all kvm__arch_<xyz> Guest/VM arch functions.
>
> These functions mostly deal with:
> 1. Guest/VM RAM initialization
> 2. Updating terminals on character read
> 3. Loading kernel and initrd images
>
> Firmware loading is not implemented currently because initially we
> will be booting kernel directly without any bootloader. In future,
> we will certainly support firmware loading.
>
> Signed-off-by: Anup Patel <anup.patel@xxxxxxx>
> ---
> riscv/include/kvm/kvm-arch.h | 15 +++++
> riscv/kvm.c | 126 +++++++++++++++++++++++++++++++++--
> 2 files changed, 135 insertions(+), 6 deletions(-)
>
> diff --git a/riscv/include/kvm/kvm-arch.h b/riscv/include/kvm/kvm-arch.h
> index 7e9c578..b3ec2d6 100644
> --- a/riscv/include/kvm/kvm-arch.h
> +++ b/riscv/include/kvm/kvm-arch.h
> @@ -45,6 +45,21 @@
> struct kvm;
>
> struct kvm_arch {
> + /*
> + * We may have to align the guest memory for virtio, so keep the
> + * original pointers here for munmap.
> + */
> + void *ram_alloc_start;
> + u64 ram_alloc_size;
> +
> + /*
> + * Guest addresses for memory layout.
> + */
> + u64 memory_guest_start;
> + u64 kern_guest_start;
> + u64 initrd_guest_start;
> + u64 initrd_size;
> + u64 dtb_guest_start;
> };
>
> static inline bool riscv_addr_in_ioport_region(u64 phys_addr)
> diff --git a/riscv/kvm.c b/riscv/kvm.c
> index e816ef5..c0d3639 100644
> --- a/riscv/kvm.c
> +++ b/riscv/kvm.c
> @@ -1,5 +1,7 @@
> #include "kvm/kvm.h"
> #include "kvm/util.h"
> +#include "kvm/8250-serial.h"
> +#include "kvm/virtio-console.h"
> #include "kvm/fdt.h"
>
> #include <linux/kernel.h>
> @@ -19,33 +21,145 @@ bool kvm__arch_cpu_supports_vm(void)
>
> void kvm__init_ram(struct kvm *kvm)
> {
> - /* TODO: */
> + int err;
> + u64 phys_start, phys_size;
> + void *host_mem;
> +
> + phys_start = RISCV_RAM;
> + phys_size = kvm->ram_size;
> + host_mem = kvm->ram_start;
> +
> + err = kvm__register_ram(kvm, phys_start, phys_size, host_mem);
> + if (err)
> + die("Failed to register %lld bytes of memory at physical "
> + "address 0x%llx [err %d]", phys_size, phys_start, err);
> +
> + kvm->arch.memory_guest_start = phys_start;
> }
>
> void kvm__arch_delete_ram(struct kvm *kvm)
> {
> - /* TODO: */
> + munmap(kvm->arch.ram_alloc_start, kvm->arch.ram_alloc_size);
> }
>
> void kvm__arch_read_term(struct kvm *kvm)
> {
> - /* TODO: */
> + serial8250__update_consoles(kvm);
> + virtio_console__inject_interrupt(kvm);
> }
>
> void kvm__arch_set_cmdline(char *cmdline, bool video)
> {
> - /* TODO: */
> }
>
> void kvm__arch_init(struct kvm *kvm, const char *hugetlbfs_path, u64 ram_size)
> {
> - /* TODO: */
> + /*
> + * Allocate guest memory. We must align our buffer to 64K to
> + * correlate with the maximum guest page size for virtio-mmio.
> + * If using THP, then our minimal alignment becomes 2M.
> + * 2M trumps 64K, so let's go with that.
> + */
> + kvm->ram_size = min(ram_size, (u64)RISCV_MAX_MEMORY(kvm));
> + kvm->arch.ram_alloc_size = kvm->ram_size + SZ_2M;
> + kvm->arch.ram_alloc_start = mmap_anon_or_hugetlbfs(kvm, hugetlbfs_path,
> + kvm->arch.ram_alloc_size);
> +
> + if (kvm->arch.ram_alloc_start == MAP_FAILED)
> + die("Failed to map %lld bytes for guest memory (%d)",
> + kvm->arch.ram_alloc_size, errno);
> +
> + kvm->ram_start = (void *)ALIGN((unsigned long)kvm->arch.ram_alloc_start,
> + SZ_2M);
> +
> + madvise(kvm->arch.ram_alloc_start, kvm->arch.ram_alloc_size,
> + MADV_MERGEABLE);
> +
> + madvise(kvm->arch.ram_alloc_start, kvm->arch.ram_alloc_size,
> + MADV_HUGEPAGE);
> }
>
> +#define FDT_ALIGN SZ_4M
> +#define INITRD_ALIGN 4
> bool kvm__arch_load_kernel_image(struct kvm *kvm, int fd_kernel, int fd_initrd,
> const char *kernel_cmdline)
> {
> - /* TODO: */
> + void *pos, *kernel_end, *limit;
> + unsigned long guest_addr, kernel_offset;
> + ssize_t file_size;
> +
> + /*
> + * Linux requires the initrd and dtb to be mapped inside lowmem,
> + * so we can't just place them at the top of memory.
> + */
> + limit = kvm->ram_start + min(kvm->ram_size, (u64)SZ_256M) - 1;
> +
> +#if __riscv_xlen == 64
> + /* Linux expects to be booted at 2M boundary for RV64 */
> + kernel_offset = 0x200000;
> +#else
> + /* Linux expects to be booted at 4M boundary for RV32 */
> + kernel_offset = 0x400000;
> +#endif
> +
> + pos = kvm->ram_start + kernel_offset;
> + kvm->arch.kern_guest_start = host_to_guest_flat(kvm, pos);
> + file_size = read_file(fd_kernel, pos, limit - pos);
> + if (file_size < 0) {
> + if (errno == ENOMEM)
> + die("kernel image too big to fit in guest memory.");
> +
> + die_perror("kernel read");
> + }
> + kernel_end = pos + file_size;
> + pr_debug("Loaded kernel to 0x%llx (%zd bytes)",
> + kvm->arch.kern_guest_start, file_size);
> +
> + /* Place FDT just after kernel at FDT_ALIGN address */
> + pos = kernel_end + FDT_ALIGN;
> + guest_addr = ALIGN(host_to_guest_flat(kvm, pos), FDT_ALIGN);
> + pos = guest_flat_to_host(kvm, guest_addr);
> + if (pos < kernel_end)
> + die("fdt overlaps with kernel image.");
> +
> + kvm->arch.dtb_guest_start = guest_addr;
> + pr_debug("Placing fdt at 0x%llx - 0x%llx",
> + kvm->arch.dtb_guest_start,
> + host_to_guest_flat(kvm, limit));
> + limit = pos;
This doesn't look right. pos points to the start of the DTB, not to the top of
free memory. You probably want to delete the line.
> +
> + /* ... and finally the initrd, if we have one. */
> + if (fd_initrd != -1) {
> + struct stat sb;
> + unsigned long initrd_start;
> +
> + if (fstat(fd_initrd, &sb))
> + die_perror("fstat");
> +
> + pos -= (sb.st_size + INITRD_ALIGN);
This too doesn't look right. You're overwriting the DTB and most likely the kernel
with the initrd.
Thanks,
Alex
> + guest_addr = ALIGN(host_to_guest_flat(kvm, pos), INITRD_ALIGN);
> + pos = guest_flat_to_host(kvm, guest_addr);
> + if (pos < kernel_end)
> + die("initrd overlaps with kernel image.");
> +
> + initrd_start = guest_addr;
> + file_size = read_file(fd_initrd, pos, limit - pos);
> + if (file_size == -1) {
> + if (errno == ENOMEM)
> + die("initrd too big to fit in guest memory.");
> +
> + die_perror("initrd read");
> + }
> +
> + kvm->arch.initrd_guest_start = initrd_start;
> + kvm->arch.initrd_size = file_size;
> + pr_debug("Loaded initrd to 0x%llx (%llu bytes)",
> + kvm->arch.initrd_guest_start,
> + kvm->arch.initrd_size);
> + } else {
> + kvm->arch.initrd_size = 0;
> + }
> +
> return true;
> }
>
