2023-09-12 14:12:16

by Thomas Gleixner

Subject: [patch V3 09/30] x86/microcode/intel: Switch to kvmalloc()

From: Thomas Gleixner <[email protected]>

Microcode blobs are getting larger and might soon reach the kmalloc()
limit. Switch over kvmalloc().

Signed-off-by: Thomas Gleixner <[email protected]>

---
arch/x86/kernel/cpu/microcode/intel.c | 50 +++++++++++++++++-----------------
1 file changed, 26 insertions(+), 24 deletions(-)
---
--- a/arch/x86/kernel/cpu/microcode/intel.c
+++ b/arch/x86/kernel/cpu/microcode/intel.c
@@ -14,7 +14,6 @@
#include <linux/earlycpio.h>
#include <linux/firmware.h>
#include <linux/uaccess.h>
-#include <linux/vmalloc.h>
#include <linux/initrd.h>
#include <linux/kernel.h>
#include <linux/slab.h>
@@ -243,7 +242,7 @@ EXPORT_SYMBOL_GPL(intel_microcode_sanity

static void update_ucode_pointer(struct microcode_intel *mc)
{
- kfree(ucode_patch_va);
+ kvfree(ucode_patch_va);

/*
* Save the virtual address for early loading and for eventual free
@@ -254,11 +253,14 @@ static void update_ucode_pointer(struct

static void save_microcode_patch(struct microcode_intel *patch)
{
- struct microcode_intel *mc;
+ unsigned int size = get_totalsize(&patch->hdr);
+ struct microcode_intel *mc = NULL;

- mc = kmemdup(patch, get_totalsize(&patch->hdr), GFP_KERNEL);
+ mc = kvmemdup(patch, size, GFP_KERNEL);
if (mc)
update_ucode_pointer(mc);
+ else
+ pr_err("Unable to allocate microcode memory size: %u\n", size);
}

/* Scan CPIO for microcode matching the boot CPUs family, model, stepping */
@@ -530,36 +532,34 @@ static enum ucode_state read_ucode_intel

if (!copy_from_iter_full(&mc_header, sizeof(mc_header), iter)) {
pr_err("error! Truncated or inaccessible header in microcode data file\n");
- break;
+ goto fail;
}

mc_size = get_totalsize(&mc_header);
if (mc_size < sizeof(mc_header)) {
pr_err("error! Bad data in microcode data file (totalsize too small)\n");
- break;
+ goto fail;
}
-
data_size = mc_size - sizeof(mc_header);
if (data_size > iov_iter_count(iter)) {
pr_err("error! Bad data in microcode data file (truncated file?)\n");
- break;
+ goto fail;
}

/* For performance reasons, reuse mc area when possible */
if (!mc || mc_size > curr_mc_size) {
- vfree(mc);
- mc = vmalloc(mc_size);
+ kvfree(mc);
+ mc = kvmalloc(mc_size, GFP_KERNEL);
if (!mc)
- break;
+ goto fail;
curr_mc_size = mc_size;
}

memcpy(mc, &mc_header, sizeof(mc_header));
data = mc + sizeof(mc_header);
if (!copy_from_iter_full(data, data_size, iter) ||
- intel_microcode_sanity_check(mc, true, MC_HEADER_TYPE_MICROCODE) < 0) {
- break;
- }
+ intel_microcode_sanity_check(mc, true, MC_HEADER_TYPE_MICROCODE) < 0)
+ goto fail;

if (cur_rev >= mc_header.rev)
continue;
@@ -567,24 +567,26 @@ static enum ucode_state read_ucode_intel
if (!intel_find_matching_signature(mc, uci->cpu_sig.sig, uci->cpu_sig.pf))
continue;

- vfree(new_mc);
+ kvfree(new_mc);
cur_rev = mc_header.rev;
new_mc = mc;
mc = NULL;
}

- vfree(mc);
-
- if (iov_iter_count(iter)) {
- vfree(new_mc);
- return UCODE_ERROR;
- }
+ if (iov_iter_count(iter))
+ goto fail;

+ kvfree(mc);
if (!new_mc)
return UCODE_NFOUND;

ucode_patch_late = (struct microcode_intel *)new_mc;
return UCODE_NEW;
+
+fail:
+ kvfree(mc);
+ kvfree(new_mc);
+ return UCODE_ERROR;
}

static bool is_blacklisted(unsigned int cpu)
@@ -643,9 +645,9 @@ static enum ucode_state request_microcod
static void finalize_late_load(int result)
{
if (!result)
- save_microcode_patch(ucode_patch_late);
-
- vfree(ucode_patch_late);
+ update_ucode_pointer(ucode_patch_late);
+ else
+ kvfree(ucode_patch_late);
ucode_patch_late = NULL;
}

2023-09-25 18:09:01

by Qiuxu Zhuo

Subject: Re: Subject: [patch V3 09/30] x86/microcode/intel: Switch to kvmalloc()

> ...
> From: Thomas Gleixner <[email protected]>
>
> Microcode blobs are getting larger and might soon reach the kmalloc()
> limit. Switch over kvmalloc().
>
> Signed-off-by: Thomas Gleixner <[email protected]>
>
> ---
> arch/x86/kernel/cpu/microcode/intel.c | 50 +++++++++++++++++-----------------
> 1 file changed, 26 insertions(+), 24 deletions(-)
> ---
> --- a/arch/x86/kernel/cpu/microcode/intel.c
> +++ b/arch/x86/kernel/cpu/microcode/intel.c
> ...
> static void save_microcode_patch(struct microcode_intel *patch)
> {
> - struct microcode_intel *mc;
> + unsigned int size = get_totalsize(&patch->hdr);
> + struct microcode_intel *mc = NULL;

No need to initialize the 'mc' to NULL as it's unconditionally
set by the following kmemdup().

>
> - mc = kmemdup(patch, get_totalsize(&patch->hdr), GFP_KERNEL);
> + mc = kvmemdup(patch, size, GFP_KERNEL);
> if (mc)
> update_ucode_pointer(mc);
> + else
> + pr_err("Unable to allocate microcode memory size: %u\n", size);
> }
>
> ...