On 11/4/24 19:05, Dionna Glaze wrote: > On init, the ccp device will make /sys/class/firmware/amd/loading etc > firmware upload API attributes available to late-load a SEV-SNP firmware > binary. > > The firmware upload api errors reported are actionable in the following > ways: > * FW_UPLOAD_ERR_HW_ERROR: the machine is in an unstable state and must > be reset. > * FW_UPLOAD_ERR_RW_ERROR: the firmware update went bad but can be > recovered by hotloading the previous firmware version. > Also used in the case that the kernel used the API wrong (bug). > * FW_UPLOAD_ERR_FW_INVALID: user error with the data provided, but no > instability is expected and no recovery actions are needed. > * FW_UPLOAD_ERR_BUSY: upload attempted at a bad time either due to > overload or the machine is in the wrong platform state. > > synthetic_restore_required: > Instead of tracking the status of whether an individual GCTX is safe for > use in a firmware command, force all following commands to fail with an > error that is indicative of needing a firmware rollback. > > To test: > 1. Build the kernel enabling SEV-SNP as normal and add CONFIG_FW_UPLOAD=y. > 2. Add the following to your kernel_cmdline: ccp.psp_init_on_probe=0. > 3.Get an AMD SEV-SNP firmware sbin appropriate to your Epyc chip model at > https://www.amd.com/en/developer/sev.html and extract to get a .sbin > file. > 4. Run the following with your sbinfile in FW: > > echo 1 > /sys/class/firmware/snp_dlfw_ex/loading > cat "${FW?}" > /sys/class/firmware/snp_dlfw_ex/data > echo 0 > /sys/class/firmware/snp_dlfw_ex/loading > > 5. Verify the firmware update message in dmesg. > > Co-developed-by: Ashish Kalra <ashish.kalra@xxxxxxx> > Signed-off-by: Ashish Kalra <ashish.kalra@xxxxxxx> > Tested-by: Ashish Kalra <ashish.kalra@xxxxxxx> > Signed-off-by: Dionna Glaze <dionnaglaze@xxxxxxxxxx> > --- > drivers/crypto/ccp/Kconfig | 2 + > drivers/crypto/ccp/sev-dev.c | 12 +- > drivers/crypto/ccp/sev-dev.h | 16 +++ > drivers/crypto/ccp/sev-fw.c | 213 +++++++++++++++++++++++++++++++++++ > 4 files changed, 241 insertions(+), 2 deletions(-) > > diff --git a/drivers/crypto/ccp/Kconfig b/drivers/crypto/ccp/Kconfig > index f394e45e11ab4..520b1c84d11f4 100644 > --- a/drivers/crypto/ccp/Kconfig > +++ b/drivers/crypto/ccp/Kconfig > @@ -39,6 +39,8 @@ config CRYPTO_DEV_SP_PSP > bool "Platform Security Processor (PSP) device" > default y > depends on CRYPTO_DEV_CCP_DD && X86_64 && AMD_IOMMU > + select FW_LOADER > + select FW_UPLOAD > help > Provide support for the AMD Platform Security Processor (PSP). > The PSP is a dedicated processor that provides support for key > diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c > index 32f7b6147905e..8c73f023b6420 100644 > --- a/drivers/crypto/ccp/sev-dev.c > +++ b/drivers/crypto/ccp/sev-dev.c > @@ -485,7 +485,7 @@ void snp_free_firmware_page(void *addr) > } > EXPORT_SYMBOL_GPL(snp_free_firmware_page); > > -static void *sev_fw_alloc(unsigned long len) > +void *sev_fw_alloc(unsigned long len) > { > struct page *page; > > @@ -853,6 +853,10 @@ static int __sev_do_cmd_locked(int cmd, void *data, int *psp_ret) > if (WARN_ON_ONCE(!data != !buf_len)) > return -EINVAL; > > + ret = sev_snp_synthetic_error(sev, psp_ret); A comment similar to what you have in the commit log would be nice above this call. > + if (ret) > + return ret; > + > /* > * Copy the incoming data to driver's scratch buffer as __pa() will not > * work for some memory, e.g. vmalloc'd addresses, and @data may not be > @@ -1523,7 +1527,7 @@ void *psp_copy_user_blob(u64 uaddr, u32 len) > } > EXPORT_SYMBOL_GPL(psp_copy_user_blob); > > -static int sev_get_api_version(void) > +int sev_get_api_version(void) > { > struct sev_device *sev = psp_master->sev_data; > struct sev_user_data_status status; > @@ -2320,6 +2324,8 @@ int sev_dev_init(struct psp_device *psp) > if (ret) > goto e_irq; > > + sev_snp_dev_init_firmware_upload(sev); > + > dev_notice(dev, "sev enabled\n"); > > return 0; > @@ -2398,6 +2404,8 @@ void sev_dev_destroy(struct psp_device *psp) > kref_put(&misc_dev->refcount, sev_exit); > > psp_clear_sev_irq_handler(psp); > + > + sev_snp_dev_init_firmware_upload(sev); Shouldn't this be the destroy call? > } > > static int snp_shutdown_on_panic(struct notifier_block *nb, > diff --git a/drivers/crypto/ccp/sev-dev.h b/drivers/crypto/ccp/sev-dev.h > index 28add34484ed1..52a423e7df84f 100644 > --- a/drivers/crypto/ccp/sev-dev.h > +++ b/drivers/crypto/ccp/sev-dev.h > @@ -59,7 +59,13 @@ struct sev_device { > bool snp_initialized; > > #ifdef CONFIG_FW_UPLOAD > + /* Lock to protect fw_cancel */ > + struct mutex fw_lock; > + struct fw_upload *fwl; > + bool fw_cancel; > + > u32 last_snp_asid; > + bool synthetic_restore_required; > u64 *snp_asid_to_gctx_pages_map; > u64 *snp_unbound_gctx_pages; > u32 snp_unbound_gctx_end; > @@ -72,12 +78,22 @@ void sev_dev_destroy(struct psp_device *psp); > void sev_pci_init(void); > void sev_pci_exit(void); > > +void *sev_fw_alloc(unsigned long len); > +int sev_get_api_version(void); > +int sev_snp_download_firmware_ex(struct sev_device *sev, const u8 *data, u32 size, int *error); > + > #ifdef CONFIG_FW_UPLOAD > void snp_cmd_bookkeeping_locked(int cmd, struct sev_device *sev, void *data); > int sev_snp_platform_init_firmware_upload(struct sev_device *sev); > +void sev_snp_dev_init_firmware_upload(struct sev_device *sev); > +void sev_snp_destroy_firmware_upload(struct sev_device *sev); > +int sev_snp_synthetic_error(struct sev_device *sev, int *psp_ret); > #else > static inline void snp_cmd_bookkeeping_locked(int cmd, struct sev_device *sev, void *data) { } > static inline int sev_snp_platform_init_firmware_upload(struct sev_device *sev) { return 0; } > +static inline void sev_snp_dev_init_firmware_upload(struct sev_device *sev) { } > +static inline void sev_snp_destroy_firmware_upload(struct sev_device *sev) { } > +static inline int sev_snp_synthetic_error(struct sev_device *sev, int *psp_ret) { return 0; } > #endif /* CONFIG_FW_UPLOAD */ > > #endif /* __SEV_DEV_H */ > diff --git a/drivers/crypto/ccp/sev-fw.c b/drivers/crypto/ccp/sev-fw.c > index 55a5a572da8f1..97ce90f2af29a 100644 > --- a/drivers/crypto/ccp/sev-fw.c > +++ b/drivers/crypto/ccp/sev-fw.c > @@ -4,6 +4,7 @@ > */ > > #include <linux/firmware.h> > +#include <linux/psp.h> > #include <linux/psp-sev.h> > > #include <asm/sev.h> > @@ -115,3 +116,215 @@ int sev_snp_platform_init_firmware_upload(struct sev_device *sev) > } > return 0; > } > + > +static enum fw_upload_err snp_dlfw_ex_prepare(struct fw_upload *fw_upload, > + const u8 *data, u32 size) > +{ > + return FW_UPLOAD_ERR_NONE; > +} > + > +static enum fw_upload_err snp_dlfw_ex_poll_complete(struct fw_upload *fw_upload) > +{ > + return FW_UPLOAD_ERR_NONE; > +} > + > +/* > + * This may be called asynchronously with an on-going update. All other > + * functions are called sequentially in a single thread. To avoid contention on > + * register accesses, only update the cancel_request flag. Other functions will > + * check this flag and handle the cancel request synchronously. > + */ > +static void snp_dlfw_ex_cancel(struct fw_upload *fw_upload) > +{ > + struct sev_device *sev = fw_upload->dd_handle; > + > + mutex_lock(&sev->fw_lock); > + sev->fw_cancel = true; > + mutex_unlock(&sev->fw_lock); Does this really need a lock? Also, I don't see it being set to false ever, so the first time an update is canceled it can never be updated again. > +} > + > +static enum fw_upload_err snp_dlfw_ex_err_translate(struct sev_device *sev, int psp_ret) > +{ > + dev_dbg(sev->dev, "Failed to update SEV firmware: %#x\n", psp_ret); Blank line. > + /* > + * Operation error: > + * HW_ERROR: Critical error. Machine needs repairs now. > + * RW_ERROR: Severe error. Roll back to the prior version to recover. > + * User error: > + * FW_INVALID: Bad input for this interface. > + * BUSY: Wrong machine state to run download_firmware_ex. > + */ > + switch (psp_ret) { > + case SEV_RET_RESTORE_REQUIRED: > + dev_warn(sev->dev, "Firmware updated but unusable\n"); > + dev_warn(sev->dev, "Need to do manual firmware rollback!!!\n"); Please keep to a single message so that other messages don't get in between when outputted. > + return FW_UPLOAD_ERR_RW_ERROR; > + case SEV_RET_SHUTDOWN_REQUIRED: > + /* No state changes made. Not a hardware error. */ > + dev_warn(sev->dev, "Firmware image cannot be live updated\n"); > + return FW_UPLOAD_ERR_FW_INVALID; > + case SEV_RET_BAD_VERSION: > + /* No state changes made. Not a hardware error. */ > + dev_warn(sev->dev, "Firmware image is not well formed\n"); > + return FW_UPLOAD_ERR_FW_INVALID; > + /* SEV-specific errors that can still happen. */ > + case SEV_RET_BAD_SIGNATURE: > + /* No state changes made. Not a hardware error. */ > + dev_warn(sev->dev, "Firmware image signature is bad\n"); > + return FW_UPLOAD_ERR_FW_INVALID; > + case SEV_RET_INVALID_PLATFORM_STATE: > + /* Calling at the wrong time. Not a hardware error. */ > + dev_warn(sev->dev, "Firmware not updated as SEV in INIT state\n"); > + return FW_UPLOAD_ERR_BUSY; > + case SEV_RET_HWSEV_RET_UNSAFE: > + dev_err(sev->dev, "Firmware is unstable. Reset your machine!!!\n"); > + return FW_UPLOAD_ERR_HW_ERROR; > + /* Kernel bug cases. */ > + case SEV_RET_INVALID_PARAM: > + dev_err(sev->dev, "Download-firmware-EX invalid parameter\n"); > + return FW_UPLOAD_ERR_RW_ERROR; > + case SEV_RET_INVALID_ADDRESS: > + dev_err(sev->dev, "Download-firmware-EX invalid address\n"); > + return FW_UPLOAD_ERR_RW_ERROR; > + default: > + dev_err(sev->dev, "Unhandled download_firmware_ex err %d\n", psp_ret); > + return FW_UPLOAD_ERR_HW_ERROR; > + } > +} > + > +static enum fw_upload_err snp_update_guest_statuses(struct sev_device *sev) snp_update_guest_contexts > +{ > + struct sev_data_snp_guest_status status_data; > + void *snp_guest_status; > + enum fw_upload_err ret; > + int error; > + > + /* > + * Force an update of guest context pages after SEV firmware > + * live update by issuing SNP_GUEST_STATUS on all guest > + * context pages. > + */ > + snp_guest_status = sev_fw_alloc(PAGE_SIZE); > + if (!snp_guest_status) > + return FW_UPLOAD_ERR_INVALID_SIZE; > + > + /* > + * After the last bound asid-to-gctx page is snp_unbound_gctx_end-many > + * unbound gctx pages that also need updating. > + */ > + for (int i = 1; i <= sev->last_snp_asid + sev->snp_unbound_gctx_end; i++) { > + if (sev->snp_asid_to_gctx_pages_map[i]) { Let reduce some indentation and do if (!sev->snp_asid_to_gctx_pages_map[i]) continue; > + status_data.gctx_paddr = sev->snp_asid_to_gctx_pages_map[i]; > + status_data.address = __psp_pa(snp_guest_status); > + ret = sev_do_cmd(SEV_CMD_SNP_GUEST_STATUS, &status_data, &error); ... and if (!ret) continue; > + if (ret) { > + /* > + * Handle race with SNP VM being destroyed/decommissoned, > + * if guest context page invalid error is returned, > + * assume guest has been destroyed. > + */ > + if (error == SEV_RET_INVALID_GUEST) > + continue; Add a blank line here. And add a comment here about synthetic_restore_required being set. > + sev->synthetic_restore_required = true; > + dev_err(sev->dev, "SNP GCTX update error: %#x\n", error); > + dev_err(sev->dev, "Roll back SNP firmware!\n"); Single message, something like: "SNP guest context update error %#x, recommend SNP firmware roll back." > + snp_free_firmware_page(snp_guest_status); This is done in the goto below, so must be removed. > + ret = FW_UPLOAD_ERR_RW_ERROR; > + goto fw_err; > + } > + } > + } > +fw_err: > + snp_free_firmware_page(snp_guest_status); > + return ret; > +} > + > +static enum fw_upload_err snp_dlfw_ex_write(struct fw_upload *fwl, const u8 *data, > + u32 offset, u32 size, u32 *written) > +{ > + struct sev_device *sev = fwl->dd_handle; > + u8 api_major, api_minor, build; > + int ret, error; > + bool cancel; > + > + if (!sev) > + return FW_UPLOAD_ERR_HW_ERROR; > + > + mutex_lock(&sev->fw_lock); > + cancel = sev->fw_cancel; > + mutex_unlock(&sev->fw_lock); Same question on the mutex, I don't see how this helps with any timing. > + > + if (cancel) > + return FW_UPLOAD_ERR_CANCELED; > + > + /* > + * SEV firmware update is a one-shot update operation, the write() > + * callback to be invoked multiple times for the same update is > + * unexpected. > + */ > + if (offset) > + return FW_UPLOAD_ERR_INVALID_SIZE; > + > + if (sev_get_api_version()) > + return FW_UPLOAD_ERR_HW_ERROR; > + > + api_major = sev->api_major; > + api_minor = sev->api_minor; > + build = sev->build; > + > + ret = sev_snp_download_firmware_ex(sev, data, size, &error); > + if (ret) > + return snp_dlfw_ex_err_translate(sev, error); > + > + ret = snp_update_guest_statuses(sev); > + if (ret) > + return ret; > + > + sev_get_api_version(); > + if (api_major != sev->api_major || api_minor != sev->api_minor || > + build != sev->build) { > + dev_info(sev->dev, "SEV firmware updated from %d.%d.%d to %d.%d.%d\n", > + api_major, api_minor, build, > + sev->api_major, sev->api_minor, sev->build); > + } else { > + dev_info(sev->dev, "SEV firmware same as old %d.%d.%d\n", > + api_major, api_minor, build); Maybe something like: "SEV firmware not updated, same as current version %d.%d.%d" > + } > + > + *written = size; Blank line. > + return FW_UPLOAD_ERR_NONE; > +} > + > +static const struct fw_upload_ops snp_dlfw_ex_ops = { > + .prepare = snp_dlfw_ex_prepare, > + .write = snp_dlfw_ex_write, > + .poll_complete = snp_dlfw_ex_poll_complete, > + .cancel = snp_dlfw_ex_cancel, > +}; > + > +void sev_snp_dev_init_firmware_upload(struct sev_device *sev) snp_init_firmware_upload > +{ > + struct fw_upload *fwl; > + > + fwl = firmware_upload_register(THIS_MODULE, sev->dev, "snp_dlfw_ex", &snp_dlfw_ex_ops, sev); > + Remove blank line. > + if (IS_ERR(fwl)) > + dev_err(sev->dev, "SEV firmware upload initialization error %ld\n", PTR_ERR(fwl)); > + > + sev->fwl = fwl; > + mutex_init(&sev->fw_lock); Probably can't happen, but shouldn't the mutex be initialized before calling firmware_upload_register()? > +} > + > +void sev_snp_destroy_firmware_upload(struct sev_device *sev) snp_destroy_firmware_upload > +{ > + firmware_upload_unregister(sev->fwl); Should this check that the sev->fwl is valid before trying to call firmware_upload_unregister()? > +} > + > +int sev_snp_synthetic_error(struct sev_device *sev, int *psp_ret) > +{ > + if (sev->synthetic_restore_required) { > + *psp_ret = SEV_RET_RESTORE_REQUIRED; > + return -EIO; > + } Blank line. Thanks, Tom > + return 0; > +}
