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These used to be allocated on stack and then moved to the SNP guest platform device (snp_guest_dev) for the reason explained in commit db10cb9b5746 ("virt: sevguest: Fix passing a stack buffer as a scatterlist target"): aesgcm_encrypt() and aesgcm_decrypt() are used for guest messages and might potentially use a crypto accelerator which requires DMA buffers to be in the linear mapping. Add a comment, pr_warn() and return -EINVAL when the buffers are not in linear mapping. Signed-off-by: Alexey Kardashevskiy Reviewed-by: Dionna Glaze --- Changes: v4: * ditched BUG_ON and ifdef --- arch/x86/coco/sev/core.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/arch/x86/coco/sev/core.c b/arch/x86/coco/sev/core.c index 818ae7b1694b..0b714df62445 100644 --- a/arch/x86/coco/sev/core.c +++ b/arch/x86/coco/sev/core.c @@ -1941,6 +1941,16 @@ int snp_send_guest_request(struct snp_msg_desc *mdes= c, struct snp_guest_req *req u64 seqno; int rc; =20 + /* + * enc_payload() calling aesgcm_encrypt() can potentially offload to HW + * which involves DMA so the data to encrypt in the SG list has to be + * in linear mapping. + */ + if (!virt_addr_valid(req->req_buf) || !virt_addr_valid(req->resp_buf)) { + pr_warn("AES-GSM buffers must be in linear mapping"); + return -EINVAL; + } + guard(mutex)(&snp_cmd_mutex); =20 /* Check if the VMPCK is not empty */ --=20 2.49.0