File 56a0f508-x86-fix-and-simplify-MTRR-overlap-checking.patch of Package xen.6121
# Commit 3272230848f36eb5bbb660216898a90048a81d9f
# Date 2016-01-21 16:11:04 +0100
# Author Jan Beulich <jbeulich@suse.com>
# Committer Jan Beulich <jbeulich@suse.com>
x86: fix (and simplify) MTRR overlap checking
Obtaining one individual range per variable range register (via
get_mtrr_range()) was bogus from the beginning, as these registers may
cover multiple disjoint ranges. Do away with that, in favor of simply
comparing masked addresses.
Also, for is_var_mtrr_overlapped()'s result to be correct when called
from mtrr_wrmsr(), generic_set_mtrr() must update saved state first.
As minor cleanup changes, constify is_var_mtrr_overlapped()'s parameter
and make mtrr_wrmsr() static.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
--- a/xen/arch/x86/cpu/mtrr/generic.c
+++ b/xen/arch/x86/cpu/mtrr/generic.c
@@ -105,7 +105,7 @@ void __init mtrr_state_warn(void)
/* Doesn't attempt to pass an error out to MTRR users
because it's quite complicated in some cases and probably not
worth it because the best error handling is to ignore it. */
-void mtrr_wrmsr(unsigned int msr, uint64_t msr_content)
+static void mtrr_wrmsr(unsigned int msr, uint64_t msr_content)
{
if (wrmsr_safe(msr, msr_content) < 0)
printk(KERN_ERR
@@ -380,8 +380,8 @@ static void generic_set_mtrr(unsigned in
if (size == 0) {
/* The invalid bit is kept in the mask, so we simply clear the
relevant mask register to disable a range. */
+ memset(vr, 0, sizeof(*vr));
mtrr_wrmsr(MTRRphysMask_MSR(reg), 0);
- memset(vr, 0, sizeof(struct mtrr_var_range));
} else {
uint32_t base_lo, base_hi, mask_lo, mask_hi;
--- a/xen/arch/x86/cpu/mtrr/mtrr.h
+++ b/xen/arch/x86/cpu/mtrr/mtrr.h
@@ -81,7 +81,6 @@ extern const struct mtrr_ops *mtrr_if;
extern unsigned int num_var_ranges;
void mtrr_state_warn(void);
-void mtrr_wrmsr(unsigned int msr, uint64_t msr_content);
extern int amd_init_mtrr(void);
extern int cyrix_init_mtrr(void);
--- a/xen/arch/x86/hvm/mtrr.c
+++ b/xen/arch/x86/hvm/mtrr.c
@@ -28,8 +28,6 @@
#include <asm/hvm/support.h>
#include <asm/hvm/cacheattr.h>
-static uint32_t size_or_mask;
-
/* Get page attribute fields (PAn) from PAT MSR. */
#define pat_cr_2_paf(pat_cr,n) ((((uint64_t)pat_cr) >> ((n)<<3)) & 0xff)
@@ -69,61 +67,28 @@ static uint8_t mtrr_epat_tbl[MTRR_NUM_TY
/* Lookup table for PAT entry of a given PAT value in host PAT. */
static uint8_t pat_entry_tbl[PAT_TYPE_NUMS];
-static void get_mtrr_range(uint64_t base_msr, uint64_t mask_msr,
- uint64_t *base, uint64_t *end)
+bool_t is_var_mtrr_overlapped(const struct mtrr_state *m)
{
- uint32_t mask_lo = (uint32_t)mask_msr;
- uint32_t mask_hi = (uint32_t)(mask_msr >> 32);
- uint32_t base_lo = (uint32_t)base_msr;
- uint32_t base_hi = (uint32_t)(base_msr >> 32);
- uint32_t size;
-
- if ( (mask_lo & 0x800) == 0 )
- {
- /* Invalid (i.e. free) range */
- *base = 0;
- *end = 0;
- return;
- }
-
- /* Work out the shifted address mask. */
- mask_lo = (size_or_mask | (mask_hi << (32 - PAGE_SHIFT)) |
- (mask_lo >> PAGE_SHIFT));
-
- /* This works correctly if size is a power of two (a contiguous range). */
- size = -mask_lo;
- *base = base_hi << (32 - PAGE_SHIFT) | base_lo >> PAGE_SHIFT;
- *end = *base + size - 1;
-}
-
-bool_t is_var_mtrr_overlapped(struct mtrr_state *m)
-{
- int32_t seg, i;
- uint64_t phys_base, phys_mask, phys_base_pre, phys_mask_pre;
- uint64_t base_pre, end_pre, base, end;
- uint8_t num_var_ranges = (uint8_t)m->mtrr_cap;
+ unsigned int seg, i;
+ unsigned int num_var_ranges = (uint8_t)m->mtrr_cap;
for ( i = 0; i < num_var_ranges; i++ )
{
- phys_base_pre = ((uint64_t*)m->var_ranges)[i*2];
- phys_mask_pre = ((uint64_t*)m->var_ranges)[i*2 + 1];
+ uint64_t base1 = m->var_ranges[i].base >> PAGE_SHIFT;
+ uint64_t mask1 = m->var_ranges[i].mask >> PAGE_SHIFT;
- get_mtrr_range(phys_base_pre, phys_mask_pre,
- &base_pre, &end_pre);
+ if ( !(m->var_ranges[i].mask & 0x800) )
+ continue;
for ( seg = i + 1; seg < num_var_ranges; seg ++ )
{
- phys_base = ((uint64_t*)m->var_ranges)[seg*2];
- phys_mask = ((uint64_t*)m->var_ranges)[seg*2 + 1];
+ uint64_t base2 = m->var_ranges[seg].base >> PAGE_SHIFT;
+ uint64_t mask2 = m->var_ranges[seg].mask >> PAGE_SHIFT;
- get_mtrr_range(phys_base, phys_mask,
- &base, &end);
+ if ( !(m->var_ranges[seg].mask & 0x800) )
+ continue;
- if ( ((base_pre != end_pre) && (base != end))
- || ((base >= base_pre) && (base <= end_pre))
- || ((end >= base_pre) && (end <= end_pre))
- || ((base_pre >= base) && (base_pre <= end))
- || ((end_pre >= base) && (end_pre <= end)) )
+ if ( (base1 & mask1 & mask2) == (base2 & mask2 & mask1) )
{
/* MTRR is overlapped. */
return 1;
@@ -172,8 +137,6 @@ static int hvm_mtrr_pat_init(void)
}
}
- size_or_mask = ~((1 << (paddr_bits - PAGE_SHIFT)) - 1);
-
return 0;
}
__initcall(hvm_mtrr_pat_init);
--- a/xen/include/asm-x86/mtrr.h
+++ b/xen/include/asm-x86/mtrr.h
@@ -83,7 +83,7 @@ extern bool_t mtrr_fix_range_msr_set(str
extern bool_t mtrr_def_type_msr_set(struct mtrr_state *v, uint64_t msr_content);
extern bool_t pat_msr_set(uint64_t *pat, uint64_t msr);
-bool_t is_var_mtrr_overlapped(struct mtrr_state *m);
+bool_t is_var_mtrr_overlapped(const struct mtrr_state *m);
bool_t mtrr_pat_not_equal(struct vcpu *vd, struct vcpu *vs);
#endif /* __ASM_X86_MTRR_H__ */
