[RFC PATCH 5/9] x86/mm: Change cpa_flush() to call flush_kernel_range() directly

Rik van Riel
2025-05-06T00:49:27Z

From: Rik van Riel <riel@fb.com>

The function cpa_flush() calls __flush_tlb_one_kernel() and
flush_tlb_all().

Replacing that with a call to flush_tlb_kernel_range() allows
cpa_flush() to make use of INVLPGB or RAR without any additional
changes.

Initialize invlpgb_count_max to 1, since flush_tlb_kernel_range()
can now be called before invlpgb_count_max has been initialized
to the value read from CPUID.

[riel: remove now unused __cpa_flush_tlb]

Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
Signed-off-by: Rik van Riel <riel@surriel.com>
---
arch/x86/kernel/cpu/amd.c | 2 +-
arch/x86/mm/pat/set_memory.c | 20 +++++++-------------
2 files changed, 8 insertions(+), 14 deletions(-)

diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index 13a48ec28f32..c85ecde786f3 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -31,7 +31,7 @@

#include "cpu.h"

-u16 invlpgb_count_max __ro_after_init;
+u16 invlpgb_count_max __ro_after_init = 1;

static inline int rdmsrq_amd_safe(unsigned msr, u64 *p)
{
diff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c
index 30ab4aced761..2454f5249329 100644
--- a/arch/x86/mm/pat/set_memory.c
+++ b/arch/x86/mm/pat/set_memory.c
@@ -399,15 +399,6 @@ static void cpa_flush_all(unsigned long cache)
on_each_cpu(__cpa_flush_all, (void *) cache, 1);
}

-static void __cpa_flush_tlb(void *data)
-{
- struct cpa_data *cpa = data;
- unsigned int i;
-
- for (i = 0; i < cpa->numpages; i++)
- flush_tlb_one_kernel(fix_addr(__cpa_addr(cpa, i)));
-}
-
static int collapse_large_pages(unsigned long addr, struct list_head *pgtables);

static void cpa_collapse_large_pages(struct cpa_data *cpa)
@@ -444,6 +435,7 @@ static void cpa_collapse_large_pages(struct cpa_data *cpa)

static void cpa_flush(struct cpa_data *cpa, int cache)
{
+ unsigned long start, end;
unsigned int i;

BUG_ON(irqs_disabled() && !early_boot_irqs_disabled);
@@ -453,10 +445,12 @@ static void cpa_flush(struct cpa_data *cpa, int cache)
goto collapse_large_pages;
}

- if (cpa->force_flush_all || cpa->numpages > tlb_single_page_flush_ceiling)
- flush_tlb_all();
- else
- on_each_cpu(__cpa_flush_tlb, cpa, 1);
+ start = fix_addr(__cpa_addr(cpa, 0));
+ end = fix_addr(__cpa_addr(cpa, cpa->numpages));
+ if (cpa->force_flush_all)
+ end = TLB_FLUSH_ALL;
+
+ flush_tlb_kernel_range(start, end);

if (!cache)
goto collapse_large_pages;
--
2.49.0