On 5/16/2017 3:36 AM, Borislav Petkov wrote:
On Tue, Apr 18, 2017 at 04:19:30PM -0500, Tom Lendacky wrote:
The SMP MP-table is built by UEFI and placed in memory in a decrypted
state. These tables are accessed using a mix of early_memremap(),
early_memunmap(), phys_to_virt() and virt_to_phys(). Change all accesses
to use early_memremap()/early_memunmap(). This allows for proper setting
of the encryption mask so that the data can be successfully accessed when
SME is active.
Signed-off-by: Tom Lendacky <thomas.lendacky@xxxxxxx>
---
arch/x86/kernel/mpparse.c | 102 +++++++++++++++++++++++++++++++--------------
1 file changed, 71 insertions(+), 31 deletions(-)
diff --git a/arch/x86/kernel/mpparse.c b/arch/x86/kernel/mpparse.c
index fd37f39..afbda41d 100644
--- a/arch/x86/kernel/mpparse.c
+++ b/arch/x86/kernel/mpparse.c
@@ -429,7 +429,21 @@ static inline void __init construct_default_ISA_mptable(int mpc_default_type)
}
}
-static struct mpf_intel *mpf_found;
+static unsigned long mpf_base;
+
+static void __init unmap_mpf(struct mpf_intel *mpf)
+{
+ early_memunmap(mpf, sizeof(*mpf));
+}
+
+static struct mpf_intel * __init map_mpf(unsigned long paddr)
+{
+ struct mpf_intel *mpf;
+
+ mpf = early_memremap(paddr, sizeof(*mpf));
+
+ return mpf;
return early_memremap(paddr, sizeof(*mpf));
Ok.
...
@@ -842,25 +873,26 @@ static int __init update_mp_table(void)
if (!enable_update_mptable)
return 0;
- mpf = mpf_found;
- if (!mpf)
+ if (!mpf_base)
return 0;
+ mpf = map_mpf(mpf_base);
+
/*
* Now see if we need to go further.
*/
if (mpf->feature1 != 0)
You're kidding, right? map_mpf() *can* return NULL.
Ugh... don't know how I forgot about that. Will fix everywhere.
Also, simplify that test:
if (mpf->feature1)
...
Ok, I can do that but I hope no one says anything about it being
unrelated to the patch. :)
- return 0;
+ goto do_unmap_mpf;
if (!mpf->physptr)
- return 0;
+ goto do_unmap_mpf;
- mpc = phys_to_virt(mpf->physptr);
+ mpc = map_mpc(mpf->physptr);
Again: error checking !!!
You have other calls to early_memremap()/map_mpf() in this patch. Please
add error checking everywhere.
Yup.
if (!smp_check_mpc(mpc, oem, str))
- return 0;
+ goto do_unmap_mpc;
- pr_info("mpf: %llx\n", (u64)virt_to_phys(mpf));
+ pr_info("mpf: %llx\n", (u64)mpf_base);
pr_info("physptr: %x\n", mpf->physptr);
if (mpc_new_phys && mpc->length > mpc_new_length) {
@@ -878,21 +910,23 @@ static int __init update_mp_table(void)
new = mpf_checksum((unsigned char *)mpc, mpc->length);
if (old == new) {
pr_info("mpc is readonly, please try alloc_mptable instead\n");
- return 0;
+ goto do_unmap_mpc;
}
pr_info("use in-position replacing\n");
} else {
mpf->physptr = mpc_new_phys;
- mpc_new = phys_to_virt(mpc_new_phys);
+ mpc_new = map_mpc(mpc_new_phys);
Ditto.
memcpy(mpc_new, mpc, mpc->length);
+ unmap_mpc(mpc);
mpc = mpc_new;
/* check if we can modify that */
if (mpc_new_phys - mpf->physptr) {
struct mpf_intel *mpf_new;
/* steal 16 bytes from [0, 1k) */
pr_info("mpf new: %x\n", 0x400 - 16);
- mpf_new = phys_to_virt(0x400 - 16);
+ mpf_new = map_mpf(0x400 - 16);
Ditto.
memcpy(mpf_new, mpf, 16);
+ unmap_mpf(mpf);
mpf = mpf_new;
mpf->physptr = mpc_new_phys;
}
--
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