* [Qemu-devel] [PATCH 1/2] AHCI: Do not (re)map FB/CLB buffers while not running
2015-03-10 21:29 [Qemu-devel] [PATCH 0/2] AHCI: avoid mapping stale guest memory John Snow
@ 2015-03-10 21:29 ` John Snow
2015-03-10 21:29 ` [Qemu-devel] [PATCH 2/2] AHCI: Protect cmd register John Snow
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: John Snow @ 2015-03-10 21:29 UTC (permalink / raw)
To: qemu-block; +Cc: pbonzini, John Snow, qemu-devel, stefanha
The FIS Receive Buffer and Command List Buffer pointers
should not be edited while the FIS receive engine or
Command Receive engines are running.
Currently, we attempt to re-map the buffers every time they
are adjusted, but while the AHCI engines are off, these registers
may contain stale values, so we should not attempt to re-map these
values until the engines are reactivated.
Reported-by: Jordan Hargrave <jharg93@gmail.com>
Signed-off-by: John Snow <jsnow@redhat.com>
---
hw/ide/ahci.c | 35 +++++++++++++++++++++--------------
1 file changed, 21 insertions(+), 14 deletions(-)
diff --git a/hw/ide/ahci.c b/hw/ide/ahci.c
index 5651372..42bbf7f 100644
--- a/hw/ide/ahci.c
+++ b/hw/ide/ahci.c
@@ -51,6 +51,8 @@ static void ahci_write_fis_d2h(AHCIDevice *ad, uint8_t *cmd_fis);
static void ahci_init_d2h(AHCIDevice *ad);
static int ahci_dma_prepare_buf(IDEDMA *dma, int is_write);
static void ahci_commit_buf(IDEDMA *dma, uint32_t tx_bytes);
+static void ahci_map_clb_address(AHCIDevice *ad);
+static void ahci_map_fis_address(AHCIDevice *ad);
static uint32_t ahci_port_read(AHCIState *s, int port, int offset)
@@ -202,25 +204,15 @@ static void ahci_port_write(AHCIState *s, int port, int offset, uint32_t val)
switch (offset) {
case PORT_LST_ADDR:
pr->lst_addr = val;
- map_page(s->as, &s->dev[port].lst,
- ((uint64_t)pr->lst_addr_hi << 32) | pr->lst_addr, 1024);
- s->dev[port].cur_cmd = NULL;
break;
case PORT_LST_ADDR_HI:
pr->lst_addr_hi = val;
- map_page(s->as, &s->dev[port].lst,
- ((uint64_t)pr->lst_addr_hi << 32) | pr->lst_addr, 1024);
- s->dev[port].cur_cmd = NULL;
break;
case PORT_FIS_ADDR:
pr->fis_addr = val;
- map_page(s->as, &s->dev[port].res_fis,
- ((uint64_t)pr->fis_addr_hi << 32) | pr->fis_addr, 256);
break;
case PORT_FIS_ADDR_HI:
pr->fis_addr_hi = val;
- map_page(s->as, &s->dev[port].res_fis,
- ((uint64_t)pr->fis_addr_hi << 32) | pr->fis_addr, 256);
break;
case PORT_IRQ_STAT:
pr->irq_stat &= ~val;
@@ -235,10 +227,12 @@ static void ahci_port_write(AHCIState *s, int port, int offset, uint32_t val)
if (pr->cmd & PORT_CMD_START) {
pr->cmd |= PORT_CMD_LIST_ON;
+ ahci_map_clb_address(&s->dev[port]);
}
if (pr->cmd & PORT_CMD_FIS_RX) {
pr->cmd |= PORT_CMD_FIS_ON;
+ ahci_map_fis_address(&s->dev[port]);
}
/* XXX usually the FIS would be pending on the bus here and
@@ -565,6 +559,21 @@ static void debug_print_fis(uint8_t *fis, int cmd_len)
#endif
}
+static void ahci_map_fis_address(AHCIDevice *ad)
+{
+ AHCIPortRegs *pr = &ad->port_regs;
+ map_page(ad->hba->as, &ad->res_fis,
+ ((uint64_t)pr->fis_addr_hi << 32) | pr->fis_addr, 256);
+}
+
+static void ahci_map_clb_address(AHCIDevice *ad)
+{
+ AHCIPortRegs *pr = &ad->port_regs;
+ ad->cur_cmd = NULL;
+ map_page(ad->hba->as, &ad->lst,
+ ((uint64_t)pr->lst_addr_hi << 32) | pr->lst_addr, 1024);
+}
+
static void ahci_write_fis_sdb(AHCIState *s, int port, uint32_t finished)
{
AHCIDevice *ad = &s->dev[port];
@@ -1366,10 +1375,8 @@ static int ahci_state_post_load(void *opaque, int version_id)
ad = &s->dev[i];
AHCIPortRegs *pr = &ad->port_regs;
- map_page(s->as, &ad->lst,
- ((uint64_t)pr->lst_addr_hi << 32) | pr->lst_addr, 1024);
- map_page(s->as, &ad->res_fis,
- ((uint64_t)pr->fis_addr_hi << 32) | pr->fis_addr, 256);
+ ahci_map_clb_address(ad);
+ ahci_map_fis_address(ad);
/*
* All pending i/o should be flushed out on a migrate. However,
* we might not have cleared the busy_slot since this is done
--
1.9.3
^ permalink raw reply related [flat|nested] 5+ messages in thread* [Qemu-devel] [PATCH 2/2] AHCI: Protect cmd register
2015-03-10 21:29 [Qemu-devel] [PATCH 0/2] AHCI: avoid mapping stale guest memory John Snow
2015-03-10 21:29 ` [Qemu-devel] [PATCH 1/2] AHCI: Do not (re)map FB/CLB buffers while not running John Snow
@ 2015-03-10 21:29 ` John Snow
2015-03-12 13:47 ` [Qemu-devel] [Qemu-block] [PATCH 0/2] AHCI: avoid mapping stale guest memory Stefan Hajnoczi
2015-03-12 13:49 ` Stefan Hajnoczi
3 siblings, 0 replies; 5+ messages in thread
From: John Snow @ 2015-03-10 21:29 UTC (permalink / raw)
To: qemu-block; +Cc: pbonzini, John Snow, qemu-devel, stefanha
Many bits in the CMD register are supposed to be strictly read-only.
We should not be deleting them on every write.
As a side-effect: pay explicit attention to when a guest marks off
the FIS Receive or Start bits, and disable the status bits ourselves,
instead of letting them implicitly fall off.
Signed-off-by: John Snow <jsnow@redhat.com>
---
hw/ide/ahci.c | 26 +++++++++++++++++++++++++-
hw/ide/ahci.h | 2 ++
2 files changed, 27 insertions(+), 1 deletion(-)
diff --git a/hw/ide/ahci.c b/hw/ide/ahci.c
index 42bbf7f..b386a25 100644
--- a/hw/ide/ahci.c
+++ b/hw/ide/ahci.c
@@ -52,7 +52,9 @@ static void ahci_init_d2h(AHCIDevice *ad);
static int ahci_dma_prepare_buf(IDEDMA *dma, int is_write);
static void ahci_commit_buf(IDEDMA *dma, uint32_t tx_bytes);
static void ahci_map_clb_address(AHCIDevice *ad);
+static void ahci_unmap_clb_address(AHCIDevice *ad);
static void ahci_map_fis_address(AHCIDevice *ad);
+static void ahci_unmap_fis_address(AHCIDevice *ad);
static uint32_t ahci_port_read(AHCIState *s, int port, int offset)
@@ -223,16 +225,24 @@ static void ahci_port_write(AHCIState *s, int port, int offset, uint32_t val)
ahci_check_irq(s);
break;
case PORT_CMD:
- pr->cmd = val & ~(PORT_CMD_LIST_ON | PORT_CMD_FIS_ON);
+ /* Block any Read-only fields from being set;
+ * including LIST_ON and FIS_ON. */
+ pr->cmd = (pr->cmd & PORT_CMD_RO_MASK) | (val & ~PORT_CMD_RO_MASK);
if (pr->cmd & PORT_CMD_START) {
pr->cmd |= PORT_CMD_LIST_ON;
ahci_map_clb_address(&s->dev[port]);
+ } else if (pr->cmd & PORT_CMD_LIST_ON) {
+ ahci_unmap_clb_address(&s->dev[port]);
+ pr->cmd = pr->cmd & ~(PORT_CMD_LIST_ON);
}
if (pr->cmd & PORT_CMD_FIS_RX) {
pr->cmd |= PORT_CMD_FIS_ON;
ahci_map_fis_address(&s->dev[port]);
+ } else if (pr->cmd & PORT_CMD_FIS_ON) {
+ ahci_unmap_fis_address(&s->dev[port]);
+ pr->cmd = pr->cmd & ~(PORT_CMD_FIS_ON);
}
/* XXX usually the FIS would be pending on the bus here and
@@ -566,6 +576,13 @@ static void ahci_map_fis_address(AHCIDevice *ad)
((uint64_t)pr->fis_addr_hi << 32) | pr->fis_addr, 256);
}
+static void ahci_unmap_fis_address(AHCIDevice *ad)
+{
+ dma_memory_unmap(ad->hba->as, ad->res_fis, 256,
+ DMA_DIRECTION_FROM_DEVICE, 256);
+ ad->res_fis = NULL;
+}
+
static void ahci_map_clb_address(AHCIDevice *ad)
{
AHCIPortRegs *pr = &ad->port_regs;
@@ -574,6 +591,13 @@ static void ahci_map_clb_address(AHCIDevice *ad)
((uint64_t)pr->lst_addr_hi << 32) | pr->lst_addr, 1024);
}
+static void ahci_unmap_clb_address(AHCIDevice *ad)
+{
+ dma_memory_unmap(ad->hba->as, ad->lst, 1024,
+ DMA_DIRECTION_FROM_DEVICE, 1024);
+ ad->lst = NULL;
+}
+
static void ahci_write_fis_sdb(AHCIState *s, int port, uint32_t finished)
{
AHCIDevice *ad = &s->dev[port];
diff --git a/hw/ide/ahci.h b/hw/ide/ahci.h
index 99aa0c9..501c002 100644
--- a/hw/ide/ahci.h
+++ b/hw/ide/ahci.h
@@ -132,6 +132,8 @@
#define PORT_CMD_ICC_PARTIAL (0x2 << 28) /* Put i/f in partial state */
#define PORT_CMD_ICC_SLUMBER (0x6 << 28) /* Put i/f in slumber state */
+#define PORT_CMD_RO_MASK 0x007dffe0 /* Which CMD bits are read only? */
+
/* ap->flags bits */
#define AHCI_FLAG_NO_NCQ (1 << 24)
#define AHCI_FLAG_IGN_IRQ_IF_ERR (1 << 25) /* ignore IRQ_IF_ERR */
--
1.9.3
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [Qemu-devel] [Qemu-block] [PATCH 0/2] AHCI: avoid mapping stale guest memory
2015-03-10 21:29 [Qemu-devel] [PATCH 0/2] AHCI: avoid mapping stale guest memory John Snow
2015-03-10 21:29 ` [Qemu-devel] [PATCH 1/2] AHCI: Do not (re)map FB/CLB buffers while not running John Snow
2015-03-10 21:29 ` [Qemu-devel] [PATCH 2/2] AHCI: Protect cmd register John Snow
@ 2015-03-12 13:47 ` Stefan Hajnoczi
2015-03-12 13:49 ` Stefan Hajnoczi
3 siblings, 0 replies; 5+ messages in thread
From: Stefan Hajnoczi @ 2015-03-12 13:47 UTC (permalink / raw)
To: John Snow; +Cc: pbonzini, stefanha, qemu-devel, qemu-block
[-- Attachment #1: Type: text/plain, Size: 1179 bytes --]
On Tue, Mar 10, 2015 at 05:29:02PM -0400, John Snow wrote:
> Currently, the AHCI device tries to re-map guest memory every time
> the low or high address registers are written to, whether or not the
> AHCI device is currently active. If the other register has stale
> information in it, this may lead to runtime failures.
>
> Reconfigure the AHCI device to ignore writes to these registers while
> the device is active, and otherwise postpone the dma memory map until
> the device becomes active.
>
> John Snow (2):
> AHCI: Do not (re)map FB/CLB buffers while not running
> AHCI: Protect cmd register
>
> hw/ide/ahci.c | 61 ++++++++++++++++++++++++++++++++++++++++++++---------------
> hw/ide/ahci.h | 2 ++
> 2 files changed, 48 insertions(+), 15 deletions(-)
hw/ide/ahci.c: In function ‘ahci_state_post_load’:
hw/ide/ahci.c:1396:23: error: unused variable ‘pr’ [-Werror=unused-variable]
AHCIPortRegs *pr = &ad->port_regs;
What happens if a malicious/buggy guest provides a bogus address? It
looks like the code still sets the "on" bit in the cmd register because
it doesn't check whether the mapped pointer is non-NULL.
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^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [Qemu-devel] [Qemu-block] [PATCH 0/2] AHCI: avoid mapping stale guest memory
2015-03-10 21:29 [Qemu-devel] [PATCH 0/2] AHCI: avoid mapping stale guest memory John Snow
` (2 preceding siblings ...)
2015-03-12 13:47 ` [Qemu-devel] [Qemu-block] [PATCH 0/2] AHCI: avoid mapping stale guest memory Stefan Hajnoczi
@ 2015-03-12 13:49 ` Stefan Hajnoczi
3 siblings, 0 replies; 5+ messages in thread
From: Stefan Hajnoczi @ 2015-03-12 13:49 UTC (permalink / raw)
To: John Snow; +Cc: pbonzini, stefanha, qemu-devel, qemu-block
[-- Attachment #1: Type: text/plain, Size: 1003 bytes --]
On Tue, Mar 10, 2015 at 05:29:02PM -0400, John Snow wrote:
> Currently, the AHCI device tries to re-map guest memory every time
> the low or high address registers are written to, whether or not the
> AHCI device is currently active. If the other register has stale
> information in it, this may lead to runtime failures.
>
> Reconfigure the AHCI device to ignore writes to these registers while
> the device is active, and otherwise postpone the dma memory map until
> the device becomes active.
>
> John Snow (2):
> AHCI: Do not (re)map FB/CLB buffers while not running
> AHCI: Protect cmd register
>
> hw/ide/ahci.c | 61 ++++++++++++++++++++++++++++++++++++++++++++---------------
> hw/ide/ahci.h | 2 ++
> 2 files changed, 48 insertions(+), 15 deletions(-)
By the way, despite the compiler warning and my comment, I'd like to get
a fix into QEMU 2.3.
I'll be away Friday 13th and Monday 16th of March, so please go ahead
without me. Kevin could review.
Stefan
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^ permalink raw reply [flat|nested] 5+ messages in thread