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bhyve: Update TX descriptor base address and host mapping on change

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bhyve sometimes segfaults when using an e1000 NIC with a Windows guest.

We are only updating our tdba and cached host mapping when the low address
register is written and when tx is set enabled, but not when the high address
or length registers are written. It is observed that Windows 10 is occasionally
enabling tx first then writing the registers in the order low, high, len. This
leaves us with a bogus base address and mapping, which causes a segfault later
when we try to copy from a descriptor that has unpredictable garbage in a
pointer.

Updating the address and mapping when any of those registers change seems to fix
that particular issue.

Reviewed by:	mav, grehan (bhyve)
MFC after:	1 week
Sponsored by:	iXsystems, Inc.
Differential Revision:	https://reviews.freebsd.org/D26798
This commit is contained in:
Ryan Moeller 2020-10-16 20:27:20 +00:00
parent 6d55b98d52
commit 60dc6bee1f
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=366771
1 changed files with 5 additions and 5 deletions
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10
usr.sbin/bhyve/pci_e82545.c
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@ -1701,18 +1701,18 @@ e82545_write_register(struct e82545_softc *sc, uint32_t offset, uint32_t value)
break;
case E1000_TDBAL(0):
sc->esc_TDBAL = value & ~0xF;
if (sc->esc_tx_enabled) {
/* Apparently legal */
if (sc->esc_tx_enabled)
e82545_tx_update_tdba(sc);
}
break;
case E1000_TDBAH(0):
//assert(!sc->esc_tx_enabled);
sc->esc_TDBAH = value;
if (sc->esc_tx_enabled)
e82545_tx_update_tdba(sc);
break;
case E1000_TDLEN(0):
//assert(!sc->esc_tx_enabled);
sc->esc_TDLEN = value & ~0xFFF0007F;
if (sc->esc_tx_enabled)
e82545_tx_update_tdba(sc);
break;
case E1000_TDH(0):
//assert(!sc->esc_tx_enabled);