In order to support firmware hotloading, the DOWNLOAD_FIRMWARE_EX command must be available. The DOWNLOAD_FIRMWARE_EX command requires cache flushing and introduces new error codes that could be returned to user space. Access to the command is through the firmware_upload API rather than through the ioctl interface to prefer a common interface. 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. CC: Sean Christopherson <seanjc@xxxxxxxxxx> CC: Paolo Bonzini <pbonzini@xxxxxxxxxx> CC: Thomas Gleixner <tglx@xxxxxxxxxxxxx> CC: Ingo Molnar <mingo@xxxxxxxxxx> CC: Borislav Petkov <bp@xxxxxxxxx> CC: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> CC: Ashish Kalra <ashish.kalra@xxxxxxx> CC: Tom Lendacky <thomas.lendacky@xxxxxxx> CC: John Allen <john.allen@xxxxxxx> CC: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> CC: "David S. Miller" <davem@xxxxxxxxxxxxx> CC: Michael Roth <michael.roth@xxxxxxx> CC: Luis Chamberlain <mcgrof@xxxxxxxxxx> CC: Russ Weight <russ.weight@xxxxxxxxx> CC: Danilo Krummrich <dakr@xxxxxxxxxx> CC: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> CC: "Rafael J. Wysocki" <rafael@xxxxxxxxxx> CC: Tianfei zhang <tianfei.zhang@xxxxxxxxx> CC: Alexey Kardashevskiy <aik@xxxxxxx> Signed-off-by: Dionna Glaze <dionnaglaze@xxxxxxxxxx> --- drivers/crypto/ccp/Kconfig | 10 ++ drivers/crypto/ccp/Makefile | 1 + drivers/crypto/ccp/sev-dev.c | 22 +-- drivers/crypto/ccp/sev-dev.h | 27 ++++ drivers/crypto/ccp/sev-fw.c | 267 +++++++++++++++++++++++++++++++++++ include/linux/psp-sev.h | 17 +++ 6 files changed, 334 insertions(+), 10 deletions(-) create mode 100644 drivers/crypto/ccp/sev-fw.c diff --git a/drivers/crypto/ccp/Kconfig b/drivers/crypto/ccp/Kconfig index f394e45e11ab4..40be991f15d28 100644 --- a/drivers/crypto/ccp/Kconfig +++ b/drivers/crypto/ccp/Kconfig @@ -46,6 +46,16 @@ config CRYPTO_DEV_SP_PSP along with software-based Trusted Execution Environment (TEE) to enable third-party trusted applications. +config CRYPTO_DEV_SP_PSP_FW_UPLOAD + bool "Platform Security Processor (PSP) device with firmware hotloading" + default y + depends on CRYPTO_DEV_SP_PSP && FW_LOADER && FW_UPLOAD + help + Provide support for AMD Platform Security Processor firmware. + The PSP firmware can be updated while no SEV or SEV-ES VMs are active. + Users of this feature should be aware of the error modes that indicate + required manual rollback or reset due to instablity. + config CRYPTO_DEV_CCP_DEBUGFS bool "Enable CCP Internals in DebugFS" default n diff --git a/drivers/crypto/ccp/Makefile b/drivers/crypto/ccp/Makefile index 394484929dae3..5ce69134ec48b 100644 --- a/drivers/crypto/ccp/Makefile +++ b/drivers/crypto/ccp/Makefile @@ -14,6 +14,7 @@ ccp-$(CONFIG_CRYPTO_DEV_SP_PSP) += psp-dev.o \ platform-access.o \ dbc.o \ hsti.o +ccp-$(CONFIG_CRYPTO_DEV_SP_PSP_FW_UPLOAD) += sev-fw.o obj-$(CONFIG_CRYPTO_DEV_CCP_CRYPTO) += ccp-crypto.o ccp-crypto-objs := ccp-crypto-main.o \ diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c index 036e8d5054fcc..498ec8a0deeca 100644 --- a/drivers/crypto/ccp/sev-dev.c +++ b/drivers/crypto/ccp/sev-dev.c @@ -227,6 +227,7 @@ static int sev_cmd_buffer_len(int cmd) case SEV_CMD_SNP_GUEST_REQUEST: return sizeof(struct sev_data_snp_guest_request); case SEV_CMD_SNP_CONFIG: return sizeof(struct sev_user_data_snp_config); case SEV_CMD_SNP_COMMIT: return sizeof(struct sev_data_snp_commit); + case SEV_CMD_SNP_DOWNLOAD_FIRMWARE_EX: return sizeof(struct sev_data_download_firmware_ex); default: return 0; } @@ -488,7 +489,7 @@ 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; @@ -856,6 +857,10 @@ 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); + 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 @@ -1632,7 +1637,7 @@ 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; @@ -1707,14 +1712,7 @@ static int sev_update_firmware(struct device *dev) return -1; } - /* - * SEV FW expects the physical address given to it to be 32 - * byte aligned. Memory allocated has structure placed at the - * beginning followed by the firmware being passed to the SEV - * FW. Allocate enough memory for data structure + alignment - * padding + SEV FW. - */ - data_size = ALIGN(sizeof(struct sev_data_download_firmware), 32); + data_size = ALIGN(sizeof(struct sev_data_download_firmware), SEV_FW_ALIGNMENT); order = get_order(firmware->size + data_size); p = alloc_pages(GFP_KERNEL, order); @@ -2378,6 +2376,8 @@ 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; @@ -2459,6 +2459,8 @@ 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); } 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 7d0fdfdda30b6..db65d2c7afe9b 100644 --- a/drivers/crypto/ccp/sev-dev.h +++ b/drivers/crypto/ccp/sev-dev.h @@ -29,6 +29,15 @@ #define SEV_CMD_COMPLETE BIT(1) #define SEV_CMDRESP_IOC BIT(0) +/* + * SEV FW expects the physical address given to it to be 32 + * byte aligned. Memory allocated has structure placed at the + * beginning followed by the firmware being passed to the SEV + * FW. Allocate enough memory for data structure + alignment + * padding + SEV FW. + */ +#define SEV_FW_ALIGNMENT 32 + struct sev_misc_dev { struct kref refcount; struct miscdevice misc; @@ -57,6 +66,11 @@ struct sev_device { bool cmd_buf_backup_active; bool snp_initialized; + +#ifdef CONFIG_FW_UPLOAD + struct fw_upload *fwl; + bool fw_cancel; +#endif /* CONFIG_FW_UPLOAD */ }; int sev_dev_init(struct psp_device *psp); @@ -73,4 +87,17 @@ struct sev_asid_data { extern struct sev_asid_data *sev_asid_data; extern u32 nr_asids, sev_min_asid, sev_max_asid, sev_es_max_asid; +void *sev_fw_alloc(unsigned long len); +int sev_get_api_version(void); + +#ifdef CONFIG_CRYPTO_DEV_SP_PSP_FW_UPLOAD +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 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_CRYPTO_DEV_SP_PSP_FW_UPLOAD */ + #endif /* __SEV_DEV_H */ diff --git a/drivers/crypto/ccp/sev-fw.c b/drivers/crypto/ccp/sev-fw.c new file mode 100644 index 0000000000000..6a87872174ee5 --- /dev/null +++ b/drivers/crypto/ccp/sev-fw.c @@ -0,0 +1,267 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * AMD Secure Encrypted Virtualization (SEV) firmware upload API + */ + +#include <linux/firmware.h> +#include <linux/psp.h> +#include <linux/psp-sev.h> + +#include <asm/sev.h> + +#include "sev-dev.h" + +static bool synthetic_restore_required; + +int sev_snp_synthetic_error(struct sev_device *sev, int *psp_ret) +{ + if (synthetic_restore_required) { + *psp_ret = SEV_RET_RESTORE_REQUIRED; + return -EIO; + } + return 0; +} + +static int sev_snp_download_firmware_ex(struct sev_device *sev, const u8 *data, u32 size, + int *error) +{ + struct sev_data_download_firmware_ex *data_ex; + int ret, order; + struct page *p; + u64 data_size; + void *fw_dest; + + data_size = ALIGN(sizeof(struct sev_data_download_firmware_ex), SEV_FW_ALIGNMENT); + + order = get_order(size + data_size); + p = alloc_pages(GFP_KERNEL, order); + if (!p) + return -ENOMEM; + + /* + * Copy firmware data to a kernel allocated contiguous + * memory region. + */ + data_ex = page_address(p); + fw_dest = page_address(p) + data_size; + memset(data_ex, 0, data_size); + memcpy(fw_dest, data, size); + + data_ex->fw_paddr = __psp_pa(fw_dest); + data_ex->fw_len = size; + data_ex->length = sizeof(struct sev_data_download_firmware_ex); + /* commit is purposefully unset for GCTX update failure to advise rollback */ + + ret = sev_do_cmd(SEV_CMD_SNP_DOWNLOAD_FIRMWARE_EX, data_ex, error); + + if (ret) + goto free_err; + + /* Need to do a DF_FLUSH after live firmware update */ + wbinvd_on_all_cpus(); + ret = sev_do_cmd(SEV_CMD_SNP_DF_FLUSH, NULL, error); + if (ret) + dev_dbg(sev->dev, "DF_FLUSH error %d\n", *error); + +free_err: + __free_pages(p, order); + return ret; +} + +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; +} + +/* Cancel can be called asynchronously, but DOWNLOAD_FIRMWARE_EX is atomic and cannot + * be canceled. There is no need to synchronize updates to fw_cancel. + */ +static void snp_dlfw_ex_cancel(struct fw_upload *fw_upload) +{ + /* fw_upload not-NULL guaranteed by firmware_upload API */ + struct sev_device *sev = fw_upload->dd_handle; + + sev->fw_cancel = true; +} + +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); + /* + * 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"); + 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) +{ + 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_es_max_asid; i++) { + if (!sev_asid_data[i].snp_context) + continue; + + status_data.gctx_paddr = __psp_pa(sev_asid_data[i].snp_context); + status_data.address = __psp_pa(snp_guest_status); + ret = sev_do_cmd(SEV_CMD_SNP_GUEST_STATUS, &status_data, &error); + 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; + synthetic_restore_required = true; + dev_err(sev->dev, "SNP GCTX update error requires rollback: %#x\n", + error); + 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) +{ + /* fwl not-NULL guaranteed by firmware_upload API */ + struct sev_device *sev = fwl->dd_handle; + u8 api_major, api_minor, build; + int ret, error; + + if (!sev) + return FW_UPLOAD_ERR_HW_ERROR; + + if (sev->fw_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); + } + + *written = size; + 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) +{ + struct fw_upload *fwl; + + fwl = firmware_upload_register(THIS_MODULE, sev->dev, "snp_dlfw_ex", &snp_dlfw_ex_ops, sev); + + if (IS_ERR(fwl)) + dev_err(sev->dev, "SEV firmware upload initialization error %ld\n", PTR_ERR(fwl)); + else + sev->fwl = fwl; +} + +void sev_snp_destroy_firmware_upload(struct sev_device *sev) +{ + if (!sev || !sev->fwl) + return; + + firmware_upload_unregister(sev->fwl); +} + diff --git a/include/linux/psp-sev.h b/include/linux/psp-sev.h index ac36b5ddf717d..b91cbdc208f49 100644 --- a/include/linux/psp-sev.h +++ b/include/linux/psp-sev.h @@ -185,6 +185,23 @@ struct sev_data_download_firmware { u32 len; /* In */ } __packed; +/** + * struct sev_data_download_firmware_ex - DOWNLOAD_FIRMWARE_EX command parameters + * + * @length: length of this command buffer + * @fw_paddr: physical address of firmware image + * @fw_len: len of the firmware image + * @commit: automatically commit the newly installed image + */ +struct sev_data_download_firmware_ex { + u32 length; /* In */ + u32 reserved; /* In */ + u64 fw_paddr; /* In */ + u32 fw_len; /* In */ + u32 commit:1; /* In */ + u32 reserved2:31; /* In */ +} __packed; + /** * struct sev_data_get_id - GET_ID command parameters * -- 2.47.0.277.g8800431eea-goog
