Re: [PATCH v10 20/38] x86, mpparse: Use memremap to map the mpf and mpc data
From: Tom Lendacky
Date: Fri Nov 03 2017 - 11:31:52 EST
On 11/3/2017 10:12 AM, Tomeu Vizoso wrote:
On 17 July 2017 at 23:10, Tom Lendacky <thomas.lendacky@xxxxxxx> 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.
Reviewed-by: Borislav Petkov <bp@xxxxxxx>
Signed-off-by: Tom Lendacky <thomas.lendacky@xxxxxxx>
---
arch/x86/kernel/mpparse.c | 98 +++++++++++++++++++++++++++++++++--------------
1 file changed, 70 insertions(+), 28 deletions(-)
Hi there,
today I played a bit with crosvm [0] and noticed that 4.14-rc7 doesn't
boot. git-bisect pointed to this patch, and reverting it indeed gets
things working again.
Anybody has an idea of why this could be?
If you send me your kernel config I'll see if I can reproduce the issue
and debug it.
Thanks,
Tom
Thanks,
Tomeu
[0] https://chromium.googlesource.com/chromiumos/platform/crosvm
diff --git a/arch/x86/kernel/mpparse.c b/arch/x86/kernel/mpparse.c
index fd37f39..5cbb317 100644
--- a/arch/x86/kernel/mpparse.c
+++ b/arch/x86/kernel/mpparse.c
@@ -429,7 +429,7 @@ static inline void __init construct_default_ISA_mptable(int mpc_default_type)
}
}
-static struct mpf_intel *mpf_found;
+static unsigned long mpf_base;
static unsigned long __init get_mpc_size(unsigned long physptr)
{
@@ -451,6 +451,7 @@ static int __init check_physptr(struct mpf_intel *mpf, unsigned int early)
size = get_mpc_size(mpf->physptr);
mpc = early_memremap(mpf->physptr, size);
+
/*
* Read the physical hardware table. Anything here will
* override the defaults.
@@ -497,12 +498,12 @@ static int __init check_physptr(struct mpf_intel *mpf, unsigned int early)
*/
void __init default_get_smp_config(unsigned int early)
{
- struct mpf_intel *mpf = mpf_found;
+ struct mpf_intel *mpf;
if (!smp_found_config)
return;
- if (!mpf)
+ if (!mpf_base)
return;
if (acpi_lapic && early)
@@ -515,6 +516,12 @@ void __init default_get_smp_config(unsigned int early)
if (acpi_lapic && acpi_ioapic)
return;
+ mpf = early_memremap(mpf_base, sizeof(*mpf));
+ if (!mpf) {
+ pr_err("MPTABLE: error mapping MP table\n");
+ return;
+ }
+
pr_info("Intel MultiProcessor Specification v1.%d\n",
mpf->specification);
#if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86_32)
@@ -529,7 +536,7 @@ void __init default_get_smp_config(unsigned int early)
/*
* Now see if we need to read further.
*/
- if (mpf->feature1 != 0) {
+ if (mpf->feature1) {
if (early) {
/*
* local APIC has default address
@@ -542,8 +549,10 @@ void __init default_get_smp_config(unsigned int early)
construct_default_ISA_mptable(mpf->feature1);
} else if (mpf->physptr) {
- if (check_physptr(mpf, early))
+ if (check_physptr(mpf, early)) {
+ early_memunmap(mpf, sizeof(*mpf));
return;
+ }
} else
BUG();
@@ -552,6 +561,8 @@ void __init default_get_smp_config(unsigned int early)
/*
* Only use the first configuration found.
*/
+
+ early_memunmap(mpf, sizeof(*mpf));
}
static void __init smp_reserve_memory(struct mpf_intel *mpf)
@@ -561,15 +572,16 @@ static void __init smp_reserve_memory(struct mpf_intel *mpf)
static int __init smp_scan_config(unsigned long base, unsigned long length)
{
- unsigned int *bp = phys_to_virt(base);
+ unsigned int *bp;
struct mpf_intel *mpf;
- unsigned long mem;
+ int ret = 0;
apic_printk(APIC_VERBOSE, "Scan for SMP in [mem %#010lx-%#010lx]\n",
base, base + length - 1);
BUILD_BUG_ON(sizeof(*mpf) != 16);
while (length > 0) {
+ bp = early_memremap(base, length);
mpf = (struct mpf_intel *)bp;
if ((*bp == SMP_MAGIC_IDENT) &&
(mpf->length == 1) &&
@@ -579,24 +591,26 @@ static int __init smp_scan_config(unsigned long base, unsigned long length)
#ifdef CONFIG_X86_LOCAL_APIC
smp_found_config = 1;
#endif
- mpf_found = mpf;
+ mpf_base = base;
- pr_info("found SMP MP-table at [mem %#010llx-%#010llx] mapped at [%p]\n",
- (unsigned long long) virt_to_phys(mpf),
- (unsigned long long) virt_to_phys(mpf) +
- sizeof(*mpf) - 1, mpf);
+ pr_info("found SMP MP-table at [mem %#010lx-%#010lx] mapped at [%p]\n",
+ base, base + sizeof(*mpf) - 1, mpf);
- mem = virt_to_phys(mpf);
- memblock_reserve(mem, sizeof(*mpf));
+ memblock_reserve(base, sizeof(*mpf));
if (mpf->physptr)
smp_reserve_memory(mpf);
- return 1;
+ ret = 1;
}
- bp += 4;
+ early_memunmap(bp, length);
+
+ if (ret)
+ break;
+
+ base += 16;
length -= 16;
}
- return 0;
+ return ret;
}
void __init default_find_smp_config(void)
@@ -838,29 +852,40 @@ static int __init update_mp_table(void)
char oem[10];
struct mpf_intel *mpf;
struct mpc_table *mpc, *mpc_new;
+ unsigned long size;
if (!enable_update_mptable)
return 0;
- mpf = mpf_found;
- if (!mpf)
+ if (!mpf_base)
+ return 0;
+
+ mpf = early_memremap(mpf_base, sizeof(*mpf));
+ if (!mpf) {
+ pr_err("MPTABLE: mpf early_memremap() failed\n");
return 0;
+ }
/*
* Now see if we need to go further.
*/
- if (mpf->feature1 != 0)
- return 0;
+ if (mpf->feature1)
+ goto do_unmap_mpf;
if (!mpf->physptr)
- return 0;
+ goto do_unmap_mpf;
- mpc = phys_to_virt(mpf->physptr);
+ size = get_mpc_size(mpf->physptr);
+ mpc = early_memremap(mpf->physptr, size);
+ if (!mpc) {
+ pr_err("MPTABLE: mpc early_memremap() failed\n");
+ goto do_unmap_mpf;
+ }
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 +903,32 @@ 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 {
+ mpc_new = early_memremap(mpc_new_phys, mpc_new_length);
+ if (!mpc_new) {
+ pr_err("MPTABLE: new mpc early_memremap() failed\n");
+ goto do_unmap_mpc;
+ }
mpf->physptr = mpc_new_phys;
- mpc_new = phys_to_virt(mpc_new_phys);
memcpy(mpc_new, mpc, mpc->length);
+ early_memunmap(mpc, size);
mpc = mpc_new;
+ size = mpc_new_length;
/* check if we can modify that */
if (mpc_new_phys - mpf->physptr) {
struct mpf_intel *mpf_new;
/* steal 16 bytes from [0, 1k) */
+ mpf_new = early_memremap(0x400 - 16, sizeof(*mpf_new));
+ if (!mpf_new) {
+ pr_err("MPTABLE: new mpf early_memremap() failed\n");
+ goto do_unmap_mpc;
+ }
pr_info("mpf new: %x\n", 0x400 - 16);
- mpf_new = phys_to_virt(0x400 - 16);
memcpy(mpf_new, mpf, 16);
+ early_memunmap(mpf, sizeof(*mpf));
mpf = mpf_new;
mpf->physptr = mpc_new_phys;
}
@@ -909,6 +945,12 @@ static int __init update_mp_table(void)
*/
replace_intsrc_all(mpc, mpc_new_phys, mpc_new_length);
+do_unmap_mpc:
+ early_memunmap(mpc, size);
+
+do_unmap_mpf:
+ early_memunmap(mpf, sizeof(*mpf));
+
return 0;
}
--
1.9.1