Date: Thu, 26 Jan 2023 20:27:17 GMT From: John Baldwin <jhb@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org Subject: git: cee36581281d - stable/13 - bhyve: Appease warning about a potentially unaligned pointer. Message-ID: <202301262027.30QKRHmK064975@gitrepo.freebsd.org>
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The branch stable/13 has been updated by jhb: URL: https://cgit.FreeBSD.org/src/commit/?id=cee36581281d4b3ce67e14dd16178d9543b5b64f commit cee36581281d4b3ce67e14dd16178d9543b5b64f Author: John Baldwin <jhb@FreeBSD.org> AuthorDate: 2022-11-29 01:10:07 +0000 Commit: John Baldwin <jhb@FreeBSD.org> CommitDate: 2023-01-26 20:24:09 +0000 bhyve: Appease warning about a potentially unaligned pointer. When initializing the device model for a PCI pass through device that uses MSI-X, bhyve reads the MSI-X capability from the real device to save a copy in the emulated PCI config space. It also saves a copy in a local struct msixcap on the stack. Since struct msixcap is packed, GCC complains that casting a pointer to the struct to a uint32_t pointer may result in an unaligned pointer. This path is not performance critical, so to appease the compiler, simply change the pointer to a char * and use memcpy to copy the 4 bytes read in each iteration of the loop. Reviewed by: corvink, bz, markj Differential Revision: https://reviews.freebsd.org/D37490 (cherry picked from commit 32b21dd2719f87811b66deeeb513acf7067f8fac) --- usr.sbin/bhyve/pci_passthru.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/usr.sbin/bhyve/pci_passthru.c b/usr.sbin/bhyve/pci_passthru.c index 049b49b67c60..285874f3925d 100644 --- a/usr.sbin/bhyve/pci_passthru.c +++ b/usr.sbin/bhyve/pci_passthru.c @@ -212,7 +212,7 @@ cfginitmsi(struct passthru_softc *sc) struct pcisel sel; struct pci_devinst *pi; struct msixcap msixcap; - uint32_t *msixcap_ptr; + char *msixcap_ptr; pi = sc->psc_pi; sel = sc->psc_sel; @@ -249,15 +249,15 @@ cfginitmsi(struct passthru_softc *sc) */ sc->psc_msix.capoff = ptr; caplen = 12; - msixcap_ptr = (uint32_t*) &msixcap; + msixcap_ptr = (char *)&msixcap; capptr = ptr; while (caplen > 0) { u32 = read_config(&sel, capptr, 4); - *msixcap_ptr = u32; + memcpy(msixcap_ptr, &u32, 4); pci_set_cfgdata32(pi, capptr, u32); caplen -= 4; capptr += 4; - msixcap_ptr++; + msixcap_ptr += 4; } } ptr = read_config(&sel, ptr + PCICAP_NEXTPTR, 1);
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