From: Joerg Roedel <jroedel@xxxxxxx>
This reverts commit 7024f60d655272bd2ca1d3a4c9e0a63319b1eea1.
The commit reverted here introduces a short-cut into the #VC handlers
memory access code which only works reliably in task context. But the
kernels #VC handler can be invoked from any context, making the
access_ok() call trigger a warning with CONFIG_DEBUG_ATOMIC_SLEEP
enabled.
Also the memcpy() used in the reverted patch is wrong, as it has no
page-fault handling. Access to kernel memory can also fault due to
kernel bugs, and those should not be reported as faults from the #VC
handler but as bugs of their real call-site, which is correctly later
done from vc_forward_exception().
Fixes: 7024f60d6552 ("x86/sev-es: Handle string port IO to kernel memory properly")
Cc: stable@xxxxxxxxxxxxxxx # v5.11
Signed-off-by: Joerg Roedel <jroedel@xxxxxxx>
---
arch/x86/kernel/sev.c | 12 ------------
1 file changed, 12 deletions(-)
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index 110b39345b40..f4f319004713 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -333,12 +333,6 @@ static enum es_result vc_write_mem(struct es_em_ctxt *ctxt,
u16 d2;
u8 d1;
- /* If instruction ran in kernel mode and the I/O buffer is in kernel space */
- if (!user_mode(ctxt->regs) && !access_ok(target, size)) {
- memcpy(dst, buf, size);
- return ES_OK;
- }
-
switch (size) {
case 1:
memcpy(&d1, buf, 1);
@@ -388,12 +382,6 @@ static enum es_result vc_read_mem(struct es_em_ctxt *ctxt,
u16 d2;
u8 d1;
- /* If instruction ran in kernel mode and the I/O buffer is in kernel space */
- if (!user_mode(ctxt->regs) && !access_ok(s, size)) {
- memcpy(buf, src, size);
- return ES_OK;
- }
-
switch (size) {
case 1:
if (__get_user(d1, s))
--
2.31.1
