Commit 0f409eae authored by Kuppuswamy Sathyanarayanan's avatar Kuppuswamy Sathyanarayanan Committed by Dave Hansen
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virt: tdx-guest: Return error for GetQuote failures 

Currently, the GetQuote request handler returns explicit errors for
hypercall-level failures and timeouts, but it ignores some VMM
failures (e.g., GET_QUOTE_SERVICE_UNAVAILABLE), for which it returns
success with a zero-length Quote. This makes error handling in
userspace more complex.

The VMM reports failures via the status field in the shared GPA header,
which is inaccessible to userspace because only the Quote payload is
exposed to userspace. Parse the status field in the kernel and return
an error for Quote failures.

This preserves existing ABI behavior as userspace already treats a
zero-length Quote as a failure.

Refer to GHCI specification [1], section "TDG.VP.VMCALL <GetQuote>",
Table 3-10 and Table 3-11 for details on the GPA header and
GetQuote status codes.

Closes: https://lore.kernel.org/linux-coco/6bdf569c-684a-4459-af7c-4430691804eb@linux.intel.com/T/#u
Closes: https://github.com/confidential-containers/guest-components/issues/823


Fixes: f4738f56 ("virt: tdx-guest: Add Quote generation support using TSM_REPORTS")
Reported-by: default avatarXiaoyao Li <xiaoyao.li@intel.com>
Signed-off-by: default avatarKuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: default avatarDave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: default avatarXiaoyao Li <xiaoyao.li@intel.com>
Reviewed-by: default avatarDan Williams <dan.j.williams@intel.com>
Acked-by: default avatarKai Huang <kai.huang@intel.com>
Tested-by: default avatarMikko Ylinen <mikko.ylinen@linux.intel.com>
Link: https://cdrdv2.intel.com/v1/dl/getContent/858626 # [1]
Link: https://patch.msgid.link/20260116230315.4023504-1-sathyanarayanan.kuppuswamy@linux.intel.com
parent 3256e41f

drivers/virt/coco/tdx-guest/tdx-guest.c

+5 −0
Original line number Diff line number Diff line
@@ -306,6 +306,11 @@ static int tdx_report_new_locked(struct tsm_report *report, void *data) 
		return ret;

	}



	if (quote_buf->status != GET_QUOTE_SUCCESS) {

		pr_debug("GetQuote request failed, status:%llx\n", quote_buf->status);

		return -EIO;

	}



	buf = kvmemdup(quote_buf->data, quote_buf->out_len, GFP_KERNEL);

	if (!buf)

		return -ENOMEM;