On 11/7/2024 5:24 PM, Dionna Glaze wrote: > 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; fw_cancel is still not being reset to false anywhere, so once set will always cancel all firmware update requests. Probably the prepare() callback can set fw_cancel to false at the start of all firmware update operations. Thanks, Ashish > +} > + > +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 > *
