crypto: ccp - simplify sev_update_firmware()

sev_do_cmd() has its own command buffer (sev->cmd_buf) with the correct
alignment, perms, etc. that it copies the command into, so prepending it to
the firmware data is unnecessary.

Switch sev_update_firmware() to using a stack allocated command in light of
this copy, and drop all of the resulting pointer math.

Signed-off-by: Tycho Andersen (AMD) <tycho@kernel.org>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c
index 8b2dfc11289bdcc6e0cca84896b484e4b4c52907..89a11a741db794773995278ad20138f361ea129f 100644 (file)
--- a/drivers/crypto/ccp/sev-dev.c
+++ b/drivers/crypto/ccp/sev-dev.c
@@ -1965,11 +1965,11 @@ static int sev_get_firmware(struct device *dev,
 /* Don't fail if SEV FW couldn't be updated. Continue with existing SEV FW */
 static int sev_update_firmware(struct device *dev)
 {
-       struct sev_data_download_firmware *data;
+       struct sev_data_download_firmware data;
        const struct firmware *firmware;
        int ret, error, order;
        struct page *p;
-       u64 data_size;
+       void *fw_blob;
 
        if (!sev_version_greater_or_equal(0, 15)) {
                dev_dbg(dev, "DOWNLOAD_FIRMWARE not supported\n");
@@ -1981,16 +1981,7 @@ 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);
-
-       order = get_order(firmware->size + data_size);
+       order = get_order(firmware->size);
        p = alloc_pages(GFP_KERNEL, order);
        if (!p) {
                ret = -1;
@@ -2001,20 +1992,20 @@ static int sev_update_firmware(struct device *dev)
         * Copy firmware data to a kernel allocated contiguous
         * memory region.
         */
-       data = page_address(p);
-       memcpy(page_address(p) + data_size, firmware->data, firmware->size);
+       fw_blob = page_address(p);
+       memcpy(fw_blob, firmware->data, firmware->size);
 
-       data->address = __psp_pa(page_address(p) + data_size);
-       data->len = firmware->size;
+       data.address = __psp_pa(fw_blob);
+       data.len = firmware->size;
 
-       ret = sev_do_cmd(SEV_CMD_DOWNLOAD_FIRMWARE, data, &error);
+       ret = sev_do_cmd(SEV_CMD_DOWNLOAD_FIRMWARE, &data, &error);
 
        /*
         * A quirk for fixing the committed TCB version, when upgrading from
         * earlier firmware version than 1.50.
         */
        if (!ret && !sev_version_greater_or_equal(1, 50))
-               ret = sev_do_cmd(SEV_CMD_DOWNLOAD_FIRMWARE, data, &error);
+               ret = sev_do_cmd(SEV_CMD_DOWNLOAD_FIRMWARE, &data, &error);
 
        if (ret)
                dev_dbg(dev, "Failed to update SEV firmware: %#x\n", error);