On Thu, Nov 24, 2011 at 3:05 AM, <zanghongyong@xxxxxxxxxx> wrote:
> From: Hongyong Zang <zanghongyong@xxxxxxxxxx>
>
> When a guest boots with ioeventfd, an error (by gdb) occurs:
> Program received signal SIGSEGV, Segmentation fault.
> 0x00000000006009cc in setup_ioeventfds (s=0x171dc40)
> at /home/louzhengwei/git_source/qemu-kvm/hw/ivshmem.c:363
> 363 for (j = 0; j < s->peers[i].nb_eventfds; j++) {
> The bug is due to accessing s->peers which is NULL.
Can you share the command-line that caused the fault?
>
> This patch uses the memory region API to replace the old one kvm_set_ioeventfd_mmio_long().
> And this patch makes memory_region_add_eventfd() called in ivshmem_read() when qemu receives
> eventfd information from ivshmem_server.
Should this patch be split into two patches, to separate the bug fix
from the other changes related to the Memory API? Unless I
misunderstand how the two are necessarily related.
Cam
>
> Signed-off-by: Hongyong Zang <zanghongyong@xxxxxxxxxx>
> ---
> hw/ivshmem.c | 41 ++++++++++++++---------------------------
> 1 files changed, 14 insertions(+), 27 deletions(-)
>
> diff --git a/hw/ivshmem.c b/hw/ivshmem.c
> index 242fbea..be26f03 100644
> --- a/hw/ivshmem.c
> +++ b/hw/ivshmem.c
> @@ -58,7 +58,6 @@ typedef struct IVShmemState {
> CharDriverState *server_chr;
> MemoryRegion ivshmem_mmio;
>
> - pcibus_t mmio_addr;
> /* We might need to register the BAR before we actually have the memory.
> * So prepare a container MemoryRegion for the BAR immediately and
> * add a subregion when we have the memory.
> @@ -346,8 +345,14 @@ static void close_guest_eventfds(IVShmemState *s, int posn)
> guest_curr_max = s->peers[posn].nb_eventfds;
>
> for (i = 0; i < guest_curr_max; i++) {
> - kvm_set_ioeventfd_mmio_long(s->peers[posn].eventfds[i],
> - s->mmio_addr + DOORBELL, (posn << 16) | i, 0);
> + if (ivshmem_has_feature(s, IVSHMEM_IOEVENTFD)) {
> + memory_region_del_eventfd(&s->ivshmem_mmio,
> + DOORBELL,
> + 4,
> + true,
> + (posn << 16) | i,
> + s->peers[posn].eventfds[i]);
> + }
> close(s->peers[posn].eventfds[i]);
> }
>
> @@ -355,22 +360,6 @@ static void close_guest_eventfds(IVShmemState *s, int posn)
> s->peers[posn].nb_eventfds = 0;
> }
>
> -static void setup_ioeventfds(IVShmemState *s) {
> -
> - int i, j;
> -
> - for (i = 0; i <= s->max_peer; i++) {
> - for (j = 0; j < s->peers[i].nb_eventfds; j++) {
> - memory_region_add_eventfd(&s->ivshmem_mmio,
> - DOORBELL,
> - 4,
> - true,
> - (i << 16) | j,
> - s->peers[i].eventfds[j]);
> - }
> - }
> -}
> -
> /* this function increase the dynamic storage need to store data about other
> * guests */
> static void increase_dynamic_storage(IVShmemState *s, int new_min_size) {
> @@ -491,10 +480,12 @@ static void ivshmem_read(void *opaque, const uint8_t * buf, int flags)
> }
>
> if (ivshmem_has_feature(s, IVSHMEM_IOEVENTFD)) {
> - if (kvm_set_ioeventfd_mmio_long(incoming_fd, s->mmio_addr + DOORBELL,
> - (incoming_posn << 16) | guest_max_eventfd, 1) < 0) {
> - fprintf(stderr, "ivshmem: ioeventfd not available\n");
> - }
> + memory_region_add_eventfd(&s->ivshmem_mmio,
> + DOORBELL,
> + 4,
> + true,
> + (incoming_posn << 16) | guest_max_eventfd,
> + incoming_fd);
> }
>
> return;
> @@ -659,10 +650,6 @@ static int pci_ivshmem_init(PCIDevice *dev)
> memory_region_init_io(&s->ivshmem_mmio, &ivshmem_mmio_ops, s,
> "ivshmem-mmio", IVSHMEM_REG_BAR_SIZE);
>
> - if (ivshmem_has_feature(s, IVSHMEM_IOEVENTFD)) {
> - setup_ioeventfds(s);
> - }
> -
> /* region for registers*/
> pci_register_bar(&s->dev, 0, PCI_BASE_ADDRESS_SPACE_MEMORY,
> &s->ivshmem_mmio);
> --
> 1.7.1
>
>
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