On Fri, Sep 14, 2018 at 01:26:58PM -0500, Brijesh Singh wrote:
Currently, the amdvi_validate_dte() assumes that a valid DTE will
always have V=1. This is not true. The V=1 means that bit[127:1] are
valid. A valid DTE can have IV=1 and V=0 (i.e pt=off, intremap=on).
Remove the V=1 check from amdvi_validate_dte(), make the caller
responsible to check for V or IV bits.
Signed-off-by: Brijesh Singh <address@hidden>
Cc: "Michael S. Tsirkin" <address@hidden>
Cc: Paolo Bonzini <address@hidden>
Cc: Richard Henderson <address@hidden>
Cc: Eduardo Habkost <address@hidden>
Cc: Marcel Apfelbaum <address@hidden>
Cc: Tom Lendacky <address@hidden>
Cc: Suravee Suthikulpanit <address@hidden>
---
hw/i386/amd_iommu.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/hw/i386/amd_iommu.c b/hw/i386/amd_iommu.c
index 1fd669f..225825e 100644
--- a/hw/i386/amd_iommu.c
+++ b/hw/i386/amd_iommu.c
@@ -807,7 +807,7 @@ static inline uint64_t amdvi_get_perms(uint64_t entry)
AMDVI_DEV_PERM_SHIFT;
}
-/* a valid entry should have V = 1 and reserved bits honoured */
+/* validate that reserved bits are honoured */
static bool amdvi_validate_dte(AMDVIState *s, uint16_t devid,
uint64_t *dte)
{
@@ -820,7 +820,7 @@ static bool amdvi_validate_dte(AMDVIState *s, uint16_t
devid,
return false;
}
- return dte[0] & AMDVI_DEV_VALID;
^^^^^^^^ [1]
+ return true;
}
For reference, this is the only caller of amdvi_validate_dte():
/* get a device table entry given the devid */
static bool amdvi_get_dte(AMDVIState *s, int devid, uint64_t *entry)
{
uint32_t offset = devid * AMDVI_DEVTAB_ENTRY_SIZE;
if (dma_memory_read(&address_space_memory, s->devtab + offset, entry,
AMDVI_DEVTAB_ENTRY_SIZE)) {
trace_amdvi_dte_get_fail(s->devtab, offset);
/* log error accessing dte */
amdvi_log_devtab_error(s, devid, s->devtab + offset, 0);
return false;
}
*entry = le64_to_cpu(*entry);
if (!amdvi_validate_dte(s, devid, entry)) { /* <--- [2] */
trace_amdvi_invalid_dte(entry[0]);
return false;
}
return true;
}
and the only caller of amdvi_get_dte() is below:
/* get a device table entry given the devid */
@@ -967,7 +967,8 @@ static void amdvi_do_translate(AMDVIAddressSpace *as,
hwaddr addr,
}
/* devices with V = 0 are not translated */
- if (!amdvi_get_dte(s, devid, entry)) {
+ if (!amdvi_get_dte(s, devid, entry) &&
+ !(entry[0] & AMDVI_DEV_VALID)) {
^^^^^ [3]
goto out;
}
This means `dte` at [1] == `entry` at [2] == `entry` at [3].
However, if amdvi_get_dte() returned false, `entry[0]` might be
uninitialized. We should check (entry[0] & AMDVI_DEV_VALID) only
if amdvi_get_dte() returned true. I assume you meant the
following:
if (!amdvi_get_dte(s, devid, entry) ||
!(entry[0] & AMDVI_DEV_VALID)) {
goto out;
}