From: Georg Kotheimer <georg.kotheimer@kernkonzept.com>
To: qemu-devel@nongnu.org, qemu-riscv@nongnu.org
Cc: Alistair Francis <alistair.francis@wdc.com>,
Georg Kotheimer <georg.kotheimer@kernkonzept.com>
Subject: [PATCH] target/riscv: Add proper two-stage lookup exception detection
Date: Thu, 11 Mar 2021 11:29:24 +0100 [thread overview]
Message-ID: <20210311102924.1400371-1-georg.kotheimer@kernkonzept.com> (raw)
The current two-stage lookup detection in riscv_cpu_do_interrupt falls
short of its purpose, as all it checks is whether two-stage address
translation either via the hypervisor-load store instructions or the
MPRV feature would be allowed.
What we really need instead is whether two-stage address translation was
active when the exception was raised. However, in riscv_cpu_do_interrupt
we do not have the information to reliably detect this. Therefore, when
we raise a memory fault exception we have to record whether two-stage
address translation is active.
Signed-off-by: Georg Kotheimer <georg.kotheimer@kernkonzept.com>
---
target/riscv/cpu.c | 1 +
target/riscv/cpu.h | 3 +++
target/riscv/cpu_helper.c | 21 ++++++++-------------
3 files changed, 12 insertions(+), 13 deletions(-)
diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
index ddea8fbeeb..865caddb06 100644
--- a/target/riscv/cpu.c
+++ b/target/riscv/cpu.c
@@ -358,6 +358,7 @@ static void riscv_cpu_reset(DeviceState *dev)
env->pc = env->resetvec;
#endif
cs->exception_index = EXCP_NONE;
+ env->two_stage_lookup = false;
env->load_res = -1;
set_default_nan_mode(1, &env->fp_status);
}
diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
index 0edb2826a2..1288ff5981 100644
--- a/target/riscv/cpu.h
+++ b/target/riscv/cpu.h
@@ -131,6 +131,9 @@ struct CPURISCVState {
target_ulong badaddr;
target_ulong guest_phys_fault_addr;
+ /* Signals whether the current exception occurred with two-stage address
+ translation active. */
+ bool two_stage_lookup;
target_ulong priv_ver;
target_ulong vext_ver;
diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c
index 2f43939fb6..2de870d3a3 100644
--- a/target/riscv/cpu_helper.c
+++ b/target/riscv/cpu_helper.c
@@ -605,6 +605,7 @@ static void raise_mmu_exception(CPURISCVState *env, target_ulong address,
g_assert_not_reached();
}
env->badaddr = address;
+ env->two_stage_lookup = two_stage;
}
hwaddr riscv_cpu_get_phys_page_debug(CPUState *cs, vaddr addr)
@@ -646,6 +647,8 @@ void riscv_cpu_do_transaction_failed(CPUState *cs, hwaddr physaddr,
}
env->badaddr = addr;
+ env->two_stage_lookup = riscv_cpu_virt_enabled(env) ||
+ riscv_cpu_two_stage_lookup(mmu_idx);
riscv_raise_exception(&cpu->env, cs->exception_index, retaddr);
}
@@ -669,6 +672,8 @@ void riscv_cpu_do_unaligned_access(CPUState *cs, vaddr addr,
g_assert_not_reached();
}
env->badaddr = addr;
+ env->two_stage_lookup = riscv_cpu_virt_enabled(env) ||
+ riscv_cpu_two_stage_lookup(mmu_idx);
riscv_raise_exception(env, cs->exception_index, retaddr);
}
#endif /* !CONFIG_USER_ONLY */
@@ -910,16 +915,8 @@ void riscv_cpu_do_interrupt(CPUState *cs)
/* handle the trap in S-mode */
if (riscv_has_ext(env, RVH)) {
target_ulong hdeleg = async ? env->hideleg : env->hedeleg;
- bool two_stage_lookup = false;
- if (env->priv == PRV_M ||
- (env->priv == PRV_S && !riscv_cpu_virt_enabled(env)) ||
- (env->priv == PRV_U && !riscv_cpu_virt_enabled(env) &&
- get_field(env->hstatus, HSTATUS_HU))) {
- two_stage_lookup = true;
- }
-
- if ((riscv_cpu_virt_enabled(env) || two_stage_lookup) && write_tval) {
+ if (env->two_stage_lookup && write_tval) {
/*
* If we are writing a guest virtual address to stval, set
* this to 1. If we are trapping to VS we will set this to 0
@@ -957,10 +954,7 @@ void riscv_cpu_do_interrupt(CPUState *cs)
riscv_cpu_set_force_hs_excep(env, 0);
} else {
/* Trap into HS mode */
- if (!two_stage_lookup) {
- env->hstatus = set_field(env->hstatus, HSTATUS_SPV,
- riscv_cpu_virt_enabled(env));
- }
+ env->hstatus = set_field(env->hstatus, HSTATUS_SPV, false);
htval = env->guest_phys_fault_addr;
}
}
@@ -1018,4 +1012,5 @@ void riscv_cpu_do_interrupt(CPUState *cs)
#endif
cs->exception_index = EXCP_NONE; /* mark handled to qemu */
+ env->two_stage_lookup = false;
}
--
2.30.1
next reply other threads:[~2021-03-11 10:31 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-11 10:29 Georg Kotheimer [this message]
2021-03-16 20:14 ` [PATCH] target/riscv: Add proper two-stage lookup exception detection Alistair Francis
2021-03-16 20:14 ` Alistair Francis
2021-03-17 18:24 ` Alistair Francis
2021-03-17 18:24 ` Alistair Francis
2021-03-19 12:49 ` Alistair Francis
2021-03-19 12:49 ` Alistair Francis
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210311102924.1400371-1-georg.kotheimer@kernkonzept.com \
--to=georg.kotheimer@kernkonzept.com \
--cc=alistair.francis@wdc.com \
--cc=qemu-devel@nongnu.org \
--cc=qemu-riscv@nongnu.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.