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multi-process: Forward PCI config space acceses to the remote process
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The Proxy Object sends the PCI config space accesses as messages
to the remote process over the communication channel

Signed-off-by: Elena Ufimtseva <elena.ufimtseva@oracle.com>
Signed-off-by: Jagannathan Raman <jag.raman@oracle.com>
Signed-off-by: John G Johnson <john.g.johnson@oracle.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: d3c94f4618813234655356c60e6f0d0362ff42d6.1611938319.git.jag.raman@oracle.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
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@elena-ufimtseva @stefanhaRH
elena-ufimtseva authored and stefanhaRH committed Feb 10, 2021
1 parent e7b2c9e commit 11ab872
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Showing 4 changed files with 132 additions and 1 deletion.
60 changes: 60 additions & 0 deletions hw/remote/message.c
View file
Expand Up @@ -15,6 +15,12 @@
#include "hw/remote/mpqemu-link.h"
#include "qapi/error.h"
#include "sysemu/runstate.h"
#include "hw/pci/pci.h"

static void process_config_write(QIOChannel *ioc, PCIDevice *dev,
MPQemuMsg *msg, Error **errp);
static void process_config_read(QIOChannel *ioc, PCIDevice *dev,
MPQemuMsg *msg, Error **errp);

void coroutine_fn mpqemu_remote_msg_loop_co(void *data)
{
Expand All @@ -40,6 +46,12 @@ void coroutine_fn mpqemu_remote_msg_loop_co(void *data)
}

switch (msg.cmd) {
case MPQEMU_CMD_PCI_CFGWRITE:
process_config_write(com->ioc, pci_dev, &msg, &local_err);
break;
case MPQEMU_CMD_PCI_CFGREAD:
process_config_read(com->ioc, pci_dev, &msg, &local_err);
break;
default:
error_setg(&local_err,
"Unknown command (%d) received for device %s"
Expand All @@ -55,3 +67,51 @@ void coroutine_fn mpqemu_remote_msg_loop_co(void *data)
qemu_system_shutdown_request(SHUTDOWN_CAUSE_GUEST_SHUTDOWN);
}
}

static void process_config_write(QIOChannel *ioc, PCIDevice *dev,
MPQemuMsg *msg, Error **errp)
{
ERRP_GUARD();
PciConfDataMsg *conf = (PciConfDataMsg *)&msg->data.pci_conf_data;
MPQemuMsg ret = { 0 };

if ((conf->addr + sizeof(conf->val)) > pci_config_size(dev)) {
error_setg(errp, "Bad address for PCI config write, pid "FMT_pid".",
getpid());
ret.data.u64 = UINT64_MAX;
} else {
pci_default_write_config(dev, conf->addr, conf->val, conf->len);
}

ret.cmd = MPQEMU_CMD_RET;
ret.size = sizeof(ret.data.u64);

if (!mpqemu_msg_send(&ret, ioc, NULL)) {
error_prepend(errp, "Error returning code to proxy, pid "FMT_pid": ",
getpid());
}
}

static void process_config_read(QIOChannel *ioc, PCIDevice *dev,
MPQemuMsg *msg, Error **errp)
{
ERRP_GUARD();
PciConfDataMsg *conf = (PciConfDataMsg *)&msg->data.pci_conf_data;
MPQemuMsg ret = { 0 };

if ((conf->addr + sizeof(conf->val)) > pci_config_size(dev)) {
error_setg(errp, "Bad address for PCI config read, pid "FMT_pid".",
getpid());
ret.data.u64 = UINT64_MAX;
} else {
ret.data.u64 = pci_default_read_config(dev, conf->addr, conf->len);
}

ret.cmd = MPQEMU_CMD_RET;
ret.size = sizeof(ret.data.u64);

if (!mpqemu_msg_send(&ret, ioc, NULL)) {
error_prepend(errp, "Error returning code to proxy, pid "FMT_pid": ",
getpid());
}
}
8 changes: 7 additions & 1 deletion hw/remote/mpqemu-link.c
View file
Expand Up @@ -207,7 +207,7 @@ uint64_t mpqemu_msg_send_and_await_reply(MPQemuMsg *msg, PCIProxyDev *pdev,
return ret;
}

if (!mpqemu_msg_valid(&msg_reply)) {
if (!mpqemu_msg_valid(&msg_reply) || msg_reply.cmd != MPQEMU_CMD_RET) {
error_setg(errp, "ERROR: Invalid reply received for command %d",
msg->cmd);
return ret;
Expand Down Expand Up @@ -242,6 +242,12 @@ bool mpqemu_msg_valid(MPQemuMsg *msg)
return false;
}
break;
case MPQEMU_CMD_PCI_CFGWRITE:
case MPQEMU_CMD_PCI_CFGREAD:
if (msg->size != sizeof(PciConfDataMsg)) {
return false;
}
break;
default:
break;
}
Expand Down
55 changes: 55 additions & 0 deletions hw/remote/proxy.c
View file
Expand Up @@ -17,6 +17,8 @@
#include "monitor/monitor.h"
#include "migration/blocker.h"
#include "qemu/sockets.h"
#include "hw/remote/mpqemu-link.h"
#include "qemu/error-report.h"

static void pci_proxy_dev_realize(PCIDevice *device, Error **errp)
{
Expand Down Expand Up @@ -65,6 +67,56 @@ static void pci_proxy_dev_exit(PCIDevice *pdev)
error_free(dev->migration_blocker);
}

static void config_op_send(PCIProxyDev *pdev, uint32_t addr, uint32_t *val,
int len, unsigned int op)
{
MPQemuMsg msg = { 0 };
uint64_t ret = -EINVAL;
Error *local_err = NULL;

msg.cmd = op;
msg.data.pci_conf_data.addr = addr;
msg.data.pci_conf_data.val = (op == MPQEMU_CMD_PCI_CFGWRITE) ? *val : 0;
msg.data.pci_conf_data.len = len;
msg.size = sizeof(PciConfDataMsg);

ret = mpqemu_msg_send_and_await_reply(&msg, pdev, &local_err);
if (local_err) {
error_report_err(local_err);
}

if (ret == UINT64_MAX) {
error_report("Failed to perform PCI config %s operation",
(op == MPQEMU_CMD_PCI_CFGREAD) ? "READ" : "WRITE");
}

if (op == MPQEMU_CMD_PCI_CFGREAD) {
*val = (uint32_t)ret;
}
}

static uint32_t pci_proxy_read_config(PCIDevice *d, uint32_t addr, int len)
{
uint32_t val;

config_op_send(PCI_PROXY_DEV(d), addr, &val, len, MPQEMU_CMD_PCI_CFGREAD);

return val;
}

static void pci_proxy_write_config(PCIDevice *d, uint32_t addr, uint32_t val,
int len)
{
/*
* Some of the functions access the copy of remote device's PCI config
* space which is cached in the proxy device. Therefore, maintain
* it updated.
*/
pci_default_write_config(d, addr, val, len);

config_op_send(PCI_PROXY_DEV(d), addr, &val, len, MPQEMU_CMD_PCI_CFGWRITE);
}

static Property proxy_properties[] = {
DEFINE_PROP_STRING("fd", PCIProxyDev, fd),
DEFINE_PROP_END_OF_LIST(),
Expand All @@ -77,6 +129,9 @@ static void pci_proxy_dev_class_init(ObjectClass *klass, void *data)

k->realize = pci_proxy_dev_realize;
k->exit = pci_proxy_dev_exit;
k->config_read = pci_proxy_read_config;
k->config_write = pci_proxy_write_config;

device_class_set_props(dc, proxy_properties);
}

Expand Down
10 changes: 10 additions & 0 deletions include/hw/remote/mpqemu-link.h
View file
Expand Up @@ -34,6 +34,9 @@
*/
typedef enum {
MPQEMU_CMD_SYNC_SYSMEM,
MPQEMU_CMD_RET,
MPQEMU_CMD_PCI_CFGWRITE,
MPQEMU_CMD_PCI_CFGREAD,
MPQEMU_CMD_MAX,
} MPQemuCmd;

Expand All @@ -43,6 +46,12 @@ typedef struct {
off_t offsets[REMOTE_MAX_FDS];
} SyncSysmemMsg;

typedef struct {
uint32_t addr;
uint32_t val;
int len;
} PciConfDataMsg;

/**
* MPQemuMsg:
* @cmd: The remote command
Expand All @@ -60,6 +69,7 @@ typedef struct {

union {
uint64_t u64;
PciConfDataMsg pci_conf_data;
SyncSysmemMsg sync_sysmem;
} data;

Expand Down

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