Re: [Xen-devel] [PATCH v6 01/12] misc/xenmicrocode: Upload a microcode blob to the hypervisor

[Sergey Dyasli <sergey.dyasli@xxxxxxxxxx>]

On 11/03/2019 07:57, Chao Gao wrote:
> This patch provides a tool for late microcode update.
> 
> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
> Signed-off-by: Chao Gao <chao.gao@xxxxxxxxx>
> ---
>  tools/libxc/include/xenctrl.h |  1 +
>  tools/libxc/xc_misc.c         | 20 ++++++++++
>  tools/misc/Makefile           |  4 ++
>  tools/misc/xenmicrocode.c     | 89 
> +++++++++++++++++++++++++++++++++++++++++++
>  4 files changed, 114 insertions(+)
>  create mode 100644 tools/misc/xenmicrocode.c
> 
> diff --git a/tools/libxc/include/xenctrl.h b/tools/libxc/include/xenctrl.h
> index 31cdda7..c69699b 100644
> --- a/tools/libxc/include/xenctrl.h
> +++ b/tools/libxc/include/xenctrl.h
> @@ -1245,6 +1245,7 @@ typedef uint32_t xc_node_to_node_dist_t;
>  int xc_physinfo(xc_interface *xch, xc_physinfo_t *info);
>  int xc_cputopoinfo(xc_interface *xch, unsigned *max_cpus,
>                     xc_cputopo_t *cputopo);
> +int xc_platform_op(xc_interface *xch, struct xen_platform_op *op);
>  int xc_numainfo(xc_interface *xch, unsigned *max_nodes,
>                  xc_meminfo_t *meminfo, uint32_t *distance);
>  int xc_pcitopoinfo(xc_interface *xch, unsigned num_devs,
> diff --git a/tools/libxc/xc_misc.c b/tools/libxc/xc_misc.c
> index 5e6714a..061c7a5 100644
> --- a/tools/libxc/xc_misc.c
> +++ b/tools/libxc/xc_misc.c
> @@ -226,6 +226,26 @@ int xc_physinfo(xc_interface *xch,
>      return 0;
>  }
>  
> +int xc_platform_op(xc_interface *xch, struct xen_platform_op *op)
> +{
> +    int ret = 0;
> +    DECLARE_PLATFORM_OP;
> +    DECLARE_HYPERCALL_BOUNCE(op, sizeof(*op), 
> XC_HYPERCALL_BUFFER_BOUNCE_BOTH);

So I've found that the bouncing in this function is not needed.
In fact, it gets in a way when Xen is returning information via xen_platform_op.
I ended up having only the single line in this function:

        return do_platform_op(xch, op);

Not sure how correct this is, but it seems to work for ucode application and
XENPF_get_cpu_version.

Thanks,
Sergey

> +
> +    if ( xc_hypercall_bounce_pre(xch, op) )
> +    {
> +        PERROR("Could not bounce xen_platform_op memory buffer");
> +        return -1;
> +    }
> +    op->interface_version = XENPF_INTERFACE_VERSION;
> +
> +    platform_op = *op;
> +    ret = do_platform_op(xch, &platform_op);
> +    xc_hypercall_bounce_post(xch, op);
> +
> +    return ret;
> +}
> +
>  int xc_cputopoinfo(xc_interface *xch, unsigned *max_cpus,
>                     xc_cputopo_t *cputopo)
>  {
> diff --git a/tools/misc/Makefile b/tools/misc/Makefile
> index 51adb6f..c297a75 100644
> --- a/tools/misc/Makefile
> +++ b/tools/misc/Makefile
> @@ -22,6 +22,7 @@ INSTALL_SBIN-$(CONFIG_X86)     += xen-hvmcrash
>  INSTALL_SBIN-$(CONFIG_X86)     += xen-hvmctx
>  INSTALL_SBIN-$(CONFIG_X86)     += xen-lowmemd
>  INSTALL_SBIN-$(CONFIG_X86)     += xen-mfndump
> +INSTALL_SBIN-$(CONFIG_X86)     += xenmicrocode
>  INSTALL_SBIN                   += xen-tmem-list-parse
>  INSTALL_SBIN                   += xencov
>  INSTALL_SBIN                   += xenlockprof
> @@ -114,4 +115,7 @@ xen-lowmemd: xen-lowmemd.o
>  xencov: xencov.o
>       $(CC) $(LDFLAGS) -o $@ $< $(LDLIBS_libxenctrl) $(APPEND_LDFLAGS)
>  
> +xenmicrocode: xenmicrocode.o
> +     $(CC) $(LDFLAGS) -o $@ $< $(LDLIBS_libxenctrl) $(APPEND_LDFLAGS)
> +
>  -include $(DEPS_INCLUDE)
> diff --git a/tools/misc/xenmicrocode.c b/tools/misc/xenmicrocode.c
> new file mode 100644
> index 0000000..e6c8a3d
> --- /dev/null
> +++ b/tools/misc/xenmicrocode.c
> @@ -0,0 +1,89 @@
> +#define _GNU_SOURCE
> +
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <sys/mman.h>
> +#include <errno.h>
> +#include <string.h>
> +#include <inttypes.h>
> +#include <unistd.h>
> +#include <sys/types.h>
> +#include <sys/stat.h>
> +#include <fcntl.h>
> +#include <xenctrl.h>
> +
> +void show_help(void)
> +{
> +    fprintf(stderr,
> +            "xenmicrocode: Xen microcode updating tool\n"
> +            "Usage: xenmicrocode <microcode blob>\n");
> +}
> +
> +int main(int argc, char *argv[])
> +{
> +    int fd, len, ret;
> +    char *filename, *buf;
> +    struct stat st;
> +    struct xen_platform_op op;
> +    xc_interface *xch;
> +    DECLARE_HYPERCALL_BUFFER(struct xenpf_microcode_update, uc);
> +
> +    if (argc < 2)
> +    {
> +        show_help();
> +        return 0;
> +    }
> +
> +    filename = argv[1];
> +    fd = open(filename, O_RDONLY);
> +    if (fd < 0) {
> +        fprintf(stderr, "Could not open %s. (err: %s)\n",
> +                filename, strerror(errno));
> +        return errno;
> +    }
> +
> +    if (stat(filename, &st) != 0) {
> +        fprintf(stderr, "Could not get the size of %s. (err: %s)\n",
> +                filename, strerror(errno));
> +        return errno;
> +    }
> +
> +    len = st.st_size;
> +    buf = mmap(0, len, PROT_READ, MAP_PRIVATE, fd, 0);
> +    if (buf == MAP_FAILED) {
> +        fprintf(stderr, "mmap failed. (error: %s)\n", strerror(errno));
> +        return errno;
> +    }
> +
> +    xch = xc_interface_open(0,0,0);
> +    if (xch == NULL)
> +    {
> +        fprintf(stderr, "Error opening xc interface. (err: %s)\n",
> +                strerror(errno));
> +        return errno;
> +    }
> +
> +    uc = xc_hypercall_buffer_alloc(xch, uc, len);
> +    if (uc == NULL)
> +        return -1;
> +
> +    memcpy(uc, buf, len);
> +    set_xen_guest_handle(op.u.microcode.data, uc);
> +    op.cmd = XENPF_microcode_update;
> +    op.interface_version = XENPF_INTERFACE_VERSION;
> +    op.u.microcode.length = len;
> +    ret = xc_platform_op(xch, &op);
> +    if ( ret )
> +        fprintf(stderr, "Failed to update microcode. (err: %d)\n", ret);
> +
> +    xc_hypercall_buffer_free(xch, uc);
> +    xc_interface_close(xch);
> +
> +    if (munmap(buf, len)) {
> +        printf("Could not unmap: %d(%s)\n", errno, strerror(errno));
> +        return errno;
> +    }
> +    close(fd);
> +
> +    return 0;
> +}
> 

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