From e4edeb73e3b9b1ba4efbf18ddb687fb210fd57f8 Mon Sep 17 00:00:00 2001 From: John Snow Date: Fri, 26 Jun 2015 21:52:46 +0200 Subject: [PATCH 1/2] ahci.c: mask unused flags when reading size PRDT DBC Message-id: <1435355567-29641-2-git-send-email-jsnow@redhat.com> Patchwork-id: 66535 O-Subject: [RHEL-7.2 qemu-kvm PATCH 1/2] ahci.c: mask unused flags when reading size PRDT DBC Bugzilla: 1205100 RH-Acked-by: Kevin Wolf RH-Acked-by: Juan Quintela RH-Acked-by: Stefan Hajnoczi From: Reza Jelveh The data byte count(DBC) read from the description information is defined for bits 21:00. Bits 30:22 are reserved and bit 31 is the Interrupt on Completion (I) flag. Completion interrupts are triggered after every transaction instead of on I-flag in QEMU. tbl_entry_size is a signed integer and improperly reading the DBC leads to a negative offset that causes sglist allocation to fail. Signed-off-by: Reza Jelveh Reviewed-by: Alexander Graf Reviewed-by: Kevin Wolf Reviewed-by: John Snow Signed-off-by: Stefan Hajnoczi (cherry picked from commit d02f8adc6d2a178bcbf77d0413f9a96fdbed53f0) Signed-off-by: John Snow Signed-off-by: Miroslav Rezanina --- hw/ide/ahci.c | 11 ++++++++--- hw/ide/ahci.h | 2 ++ 2 files changed, 10 insertions(+), 3 deletions(-) diff --git a/hw/ide/ahci.c b/hw/ide/ahci.c index 011e796..7f3927a 100644 --- a/hw/ide/ahci.c +++ b/hw/ide/ahci.c @@ -635,6 +635,11 @@ static void ahci_write_fis_d2h(AHCIDevice *ad, uint8_t *cmd_fis) } } +static int prdt_tbl_entry_size(const AHCI_SG *tbl) +{ + return (le32_to_cpu(tbl->flags_size) & AHCI_PRDT_SIZE_MASK) + 1; +} + static int ahci_populate_sglist(AHCIDevice *ad, QEMUSGList *sglist, int offset) { AHCICmdHdr *cmd = ad->cur_cmd; @@ -675,7 +680,7 @@ static int ahci_populate_sglist(AHCIDevice *ad, QEMUSGList *sglist, int offset) sum = 0; for (i = 0; i < sglist_alloc_hint; i++) { /* flags_size is zero-based */ - tbl_entry_size = (le32_to_cpu(tbl[i].flags_size) + 1); + tbl_entry_size = prdt_tbl_entry_size(&tbl[i]); if (offset <= (sum + tbl_entry_size)) { off_idx = i; off_pos = offset - sum; @@ -693,12 +698,12 @@ static int ahci_populate_sglist(AHCIDevice *ad, QEMUSGList *sglist, int offset) qemu_sglist_init(sglist, (sglist_alloc_hint - off_idx), ad->hba->dma); qemu_sglist_add(sglist, le64_to_cpu(tbl[off_idx].addr + off_pos), - le32_to_cpu(tbl[off_idx].flags_size) + 1 - off_pos); + prdt_tbl_entry_size(&tbl[off_idx]) - off_pos); for (i = off_idx + 1; i < sglist_alloc_hint; i++) { /* flags_size is zero-based */ qemu_sglist_add(sglist, le64_to_cpu(tbl[i].addr), - le32_to_cpu(tbl[i].flags_size) + 1); + prdt_tbl_entry_size(&tbl[i])); } } diff --git a/hw/ide/ahci.h b/hw/ide/ahci.h index 85f37fe..47c0961 100644 --- a/hw/ide/ahci.h +++ b/hw/ide/ahci.h @@ -201,6 +201,8 @@ #define AHCI_COMMAND_TABLE_ACMD 0x40 +#define AHCI_PRDT_SIZE_MASK 0x3fffff + #define IDE_FEATURE_DMA 1 #define READ_FPDMA_QUEUED 0x60 -- 1.8.3.1