Ping: [PATCH] hw/nvme: Add options to override hardcoded values

[Mauricio Sandt <mauricio@mailbox.org>]

[-- Attachment #1: Type: text/plain, Size: 4182 bytes --]

https://patchew.org/QEMU/20220611223509.32280-1-mauricio@mailbox.org/
https://lore.kernel.org/qemu-devel/20220611223509.32280-1-mauricio@mailbox.org/

On 12/06/2022 00:35, Mauricio Sandt wrote:
> This small patch is the result of some recent malware research I did
> in a QEMU VM. The malware used multiple ways of querying info from
> the VM disk and I needed a clean way to change those values from the
> hypervisor.
>
> I believe this functionality could be useful to more people from multiple
> fields, sometimes you just want to change some default values and having
> them hardcoded in the sourcecode makes that much harder.
>
> This patch adds three config parameters to the nvme device, all of them
> are optional to not break anything. If any of them are not specified,
> the previous (before this patch) default is used.
>
> -model - This takes a string and sets it as the devices model name.
> If you don't specify this parameter, the default is "QEMU NVMe Ctrl".
>
> -firmware - The firmware version string, max 8 ascii characters.
> The default is whatever `QEMU_VERSION` evaluates to.
>
> -nqn_override - Allows to set a custom nqn on the nvme device.
> Only used if there is no subsystem. This string should be in the same
> format as the default "nqn.2019-08.org.qemu:...", but there is no
> validation for that. Its up to the user to provide a valid string.
>
> Signed-off-by: Mauricio Sandt<mauricio@mailbox.org>
> ---
>   hw/nvme/ctrl.c | 16 +++++++++++++---
>   hw/nvme/nvme.h |  3 +++
>   2 files changed, 16 insertions(+), 3 deletions(-)
>
> diff --git a/hw/nvme/ctrl.c b/hw/nvme/ctrl.c
> index 1e6e0fcad9..0e67217a63 100644
> --- a/hw/nvme/ctrl.c
> +++ b/hw/nvme/ctrl.c
> @@ -6697,8 +6697,13 @@ static void nvme_init_subnqn(NvmeCtrl *n)
>       NvmeIdCtrl *id = &n->id_ctrl;
>   
>       if (!subsys) {
> -        snprintf((char *)id->subnqn, sizeof(id->subnqn),
> +        if (n->params.nqn_override) {
> +            snprintf((char *)id->subnqn, sizeof(id->subnqn),
> +                 "%s", n->params.nqn_override);
> +        } else {
> +            snprintf((char *)id->subnqn, sizeof(id->subnqn),
>                    "nqn.2019-08.org.qemu:%s", n->params.serial);
> +        }
>       } else {
>           pstrcpy((char *)id->subnqn, sizeof(id->subnqn), (char*)subsys->subnqn);
>       }
> @@ -6712,8 +6717,10 @@ static void nvme_init_ctrl(NvmeCtrl *n, PCIDevice *pci_dev)
>   
>       id->vid = cpu_to_le16(pci_get_word(pci_conf + PCI_VENDOR_ID));
>       id->ssvid = cpu_to_le16(pci_get_word(pci_conf + PCI_SUBSYSTEM_VENDOR_ID));
> -    strpadcpy((char *)id->mn, sizeof(id->mn), "QEMU NVMe Ctrl", ' ');
> -    strpadcpy((char *)id->fr, sizeof(id->fr), QEMU_VERSION, ' ');
> +    strpadcpy((char *)id->mn, sizeof(id->mn),
> +            n->params.model ? n->params.model : "QEMU NVMe Ctrl", ' ');
> +    strpadcpy((char *)id->fr, sizeof(id->fr),
> +            n->params.firmware ? n->params.firmware : QEMU_VERSION, ' ');
>       strpadcpy((char *)id->sn, sizeof(id->sn), n->params.serial, ' ');
>   
>       id->cntlid = cpu_to_le16(n->cntlid);
> @@ -6913,6 +6920,9 @@ static Property nvme_props[] = {
>       DEFINE_PROP_LINK("subsys", NvmeCtrl, subsys, TYPE_NVME_SUBSYS,
>                        NvmeSubsystem *),
>       DEFINE_PROP_STRING("serial", NvmeCtrl, params.serial),
> +    DEFINE_PROP_STRING("model", NvmeCtrl, params.model),
> +    DEFINE_PROP_STRING("nqn_override", NvmeCtrl, params.nqn_override),
> +    DEFINE_PROP_STRING("firmware", NvmeCtrl, params.firmware),
>       DEFINE_PROP_UINT32("cmb_size_mb", NvmeCtrl, params.cmb_size_mb, 0),
>       DEFINE_PROP_UINT32("num_queues", NvmeCtrl, params.num_queues, 0),
>       DEFINE_PROP_UINT32("max_ioqpairs", NvmeCtrl, params.max_ioqpairs, 64),
> diff --git a/hw/nvme/nvme.h b/hw/nvme/nvme.h
> index e41771604f..45bcf3e02e 100644
> --- a/hw/nvme/nvme.h
> +++ b/hw/nvme/nvme.h
> @@ -394,6 +394,9 @@ typedef struct NvmeCQueue {
>   
>   typedef struct NvmeParams {
>       char     *serial;
> +    char     *model;
> +    char     *firmware;
> +    char     *nqn_override;
>       uint32_t num_queues; /* deprecated since 5.1 */
>       uint32_t max_ioqpairs;
>       uint16_t msix_qsize;

[-- Attachment #2: Type: text/html, Size: 4798 bytes --]