Download raw body.
psp(4): Avoid sleep/wakeup race by raising SPL
Hi,
got some more feedback, thanks! Updated diff below.
Take care,
HJ.
----------------------------------------------------------------
commit a2d38daeedc1921e1d1a5befd13d3438f7d277c8
Author: Hans-Joerg Hoexer <hshoexer@genua.de>
Date: Mon Nov 4 17:09:24 2024 +0100
psp(4): Avoid sleep/wakeup race; make interrupt MP safe
And therefore pspioctl() can release the kernel lock.
diff --git a/sys/dev/ic/psp.c b/sys/dev/ic/psp.c
index 72978ca5d4e..8814a13e7a0 100644
--- a/sys/dev/ic/psp.c
+++ b/sys/dev/ic/psp.c
@@ -20,12 +20,13 @@
#include <sys/systm.h>
#include <sys/device.h>
#include <sys/malloc.h>
+#include <sys/mutex.h>
#include <sys/pledge.h>
+#include <sys/proc.h>
#include <sys/rwlock.h>
#include <machine/bus.h>
-#include <sys/proc.h>
#include <uvm/uvm.h>
#include <crypto/xform.h>
@@ -56,6 +57,7 @@ struct psp_softc {
caddr_t sc_tmr_kva;
struct rwlock sc_lock;
+ struct mutex psp_lock;
uint32_t sc_flags;
#define PSPF_INITIALIZED 0x1
@@ -90,8 +92,10 @@ psp_sev_intr(void *arg)
struct psp_softc *sc = (struct psp_softc *)csc->sc_psp;
uint32_t status;
+ mtx_enter(&sc->psp_lock);
status = bus_space_read_4(sc->sc_iot, sc->sc_ioh, sc->sc_reg_intsts);
bus_space_write_4(sc->sc_iot, sc->sc_ioh, sc->sc_reg_intsts, status);
+ mtx_leave(&sc->psp_lock);
if (!(status & PSP_CMDRESP_COMPLETE))
return (0);
@@ -137,6 +141,7 @@ psp_attach(struct device *parent, struct device *self, void *aux)
printf(" vers %d,", arg->version);
rw_init(&sc->sc_lock, "psp_lock");
+ mtx_init(&sc->psp_lock, IPL_BIO);
/* create and map SEV command buffer */
sc->sc_cmd_size = size = PAGE_SIZE;
@@ -209,7 +214,8 @@ ccp_wait(struct psp_softc *sc, uint32_t *status, int poll)
return (1);
}
- if (tsleep_nsec(sc, PWAIT, "psp", SEC_TO_NSEC(2)) == EWOULDBLOCK)
+ if (msleep_nsec(sc, &sc->psp_lock, PWAIT, "psp", SEC_TO_NSEC(2))
+ == EWOULDBLOCK)
return (1);
cmdword = bus_space_read_4(sc->sc_iot, sc->sc_ioh, sc->sc_reg_cmdresp);
@@ -223,6 +229,7 @@ static int
ccp_docmd(struct psp_softc *sc, int cmd, uint64_t paddr)
{
uint32_t plo, phi, cmdword, status;
+ int ret;
plo = ((paddr >> 0) & 0xffffffff);
phi = ((paddr >> 32) & 0xffffffff);
@@ -230,11 +237,14 @@ ccp_docmd(struct psp_softc *sc, int cmd, uint64_t paddr)
if (!cold)
cmdword |= PSP_CMDRESP_IOC;
+ mtx_enter(&sc->psp_lock);
bus_space_write_4(sc->sc_iot, sc->sc_ioh, sc->sc_reg_addrlo, plo);
bus_space_write_4(sc->sc_iot, sc->sc_ioh, sc->sc_reg_addrhi, phi);
bus_space_write_4(sc->sc_iot, sc->sc_ioh, sc->sc_reg_cmdresp, cmdword);
- if (ccp_wait(sc, &status, cold))
+ ret = ccp_wait(sc, &status, cold);
+ mtx_leave(&sc->psp_lock);
+ if (ret)
return (1);
/* Did PSP sent a response code? */
@@ -783,6 +793,8 @@ pspioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct proc *p)
if (sc == NULL)
return (ENXIO);
+ KERNEL_UNLOCK();
+
rw_enter_write(&sc->sc_lock);
switch (cmd) {
@@ -840,6 +852,8 @@ pspioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct proc *p)
rw_exit_write(&sc->sc_lock);
+ KERNEL_LOCK();
+
return (ret);
}
diff --git a/sys/dev/pci/psp_pci.c b/sys/dev/pci/psp_pci.c
index e1356ceeb8a..09864796611 100644
--- a/sys/dev/pci/psp_pci.c
+++ b/sys/dev/pci/psp_pci.c
@@ -81,8 +81,8 @@ psp_pci_intr_map(struct ccp_softc *sc, struct pci_attach_args *pa)
}
intrstr = pci_intr_string(pa->pa_pc, ih);
- sc->sc_irqh = pci_intr_establish(pa->pa_pc, ih, IPL_BIO, psp_sev_intr,
- sc, sc->sc_dev.dv_xname);
+ sc->sc_irqh = pci_intr_establish(pa->pa_pc, ih, IPL_BIO | IPL_MPSAFE,
+ psp_sev_intr, sc, sc->sc_dev.dv_xname);
if (sc->sc_irqh != NULL)
printf(": %s", intrstr);
}
psp(4): Avoid sleep/wakeup race by raising SPL