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11415 commits

Author SHA1 Message Date
Daniel Henrique Barboza
cdfb290569
target/riscv: remove RISCV_FEATURE_DEBUG
RISCV_FEATURE_DEBUG will always follow the value defined by
cpu->cfg.debug flag. Read the flag instead.

Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Weiwei Li <liweiwei@iscas.ac.cn>
Reviewed-by: Bin Meng <bmeng@tinylab.org>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: LIU Zhiwei <zhiwei_liu@linux.alibaba.com>
Message-ID: <20230222185205.355361-5-dbarboza@ventanamicro.com>
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-03-01 13:47:10 -08:00
Daniel Henrique Barboza
54bd9b6ec3
target/riscv: allow MISA writes as experimental
At this moment, and apparently since ever, we have no way of enabling
RISCV_FEATURE_MISA. This means that all the code from write_misa(), all
the nuts and bolts that handles how to properly write this CSR, has
always been a no-op as well because write_misa() will always exit
earlier.

This seems to be benign in the majority of cases. Booting an Ubuntu
'virt' guest and logging all the calls to 'write_misa' shows that no
writes to MISA CSR was attempted. Writing MISA, i.e. enabling/disabling
RISC-V extensions after the machine is powered on, seems to be a niche
use.

After discussions in the mailing list, most notably in [1], we reached
the consensus that this code is not suited to be exposed to users
because it's not well tested, but at the same time removing it is a bit
extreme because we would like to fix it, and it's easier to do so with
the code available to use instead of fetching it from git log.

The approach taken here is to get rid of RISCV_FEATURE_MISA altogether
and use a new experimental flag called x-misa-w. The default value is
false, meaning that we're keeping the existing behavior of doing nothing
if a write_misa() is attempted. As with any existing experimental flag,
x-misa-w is also a temporary flag that we need to remove once we fix
write_misa().

[1] https://lists.gnu.org/archive/html/qemu-devel/2023-02/msg05092.html

Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Weiwei Li <liweiwei@iscas.ac.cn>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Bin Meng <bmeng@tinylab.org>
Reviewed-by: Weiwei Li<liweiwei@iscas.ac.cn>
Reviewed-by: LIU Zhiwei <zhiwei_liu@linux.alibaba.com>
Message-ID: <20230222185205.355361-4-dbarboza@ventanamicro.com>
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-03-01 13:47:10 -08:00
Daniel Henrique Barboza
5b17fefb90
target/riscv: do not mask unsupported QEMU extensions in write_misa()
The masking done using env->misa_ext_mask already filters any extension
that QEMU doesn't support. If the hart supports the extension then QEMU
supports it as well.

If the masking done by env->misa_ext_mask is somehow letting unsupported
QEMU extensions pass by, misa_ext_mask itself needs to be fixed instead.

Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Weiwei Li <liweiwei@iscas.ac.cn>
Reviewed-by: Bin Meng <bmeng@tinylab.org>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Message-ID: <20230222185205.355361-3-dbarboza@ventanamicro.com>
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-03-01 13:47:09 -08:00
Daniel Henrique Barboza
d4ea711704
target/riscv: introduce riscv_cpu_cfg()
We're going to do changes that requires accessing the RISCVCPUConfig
struct from the RISCVCPU, having access only to a CPURISCVState 'env'
pointer. Add a helper to make the code easier to read.

Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Bin Meng <bmeng@tinylab.org>
Reviewed-by: LIU Zhiwei <zhiwei_liu@linux.alibaba.com>
Reviewed-by: Weiwei Li <liweiwei@iscas.ac.cn>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-ID: <20230222185205.355361-2-dbarboza@ventanamicro.com>
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-03-01 13:47:08 -08:00
Richard Henderson
177bbc81b5 target/xtensa: Don't use tcg_temp_local_new_*
Since tcg_temp_new_* is now identical, use those.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-03-01 07:33:28 -10:00
Richard Henderson
9723281fbb target/ppc: Don't use tcg_temp_local_new
Since tcg_temp_new is now identical, use that.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-03-01 07:33:28 -10:00
Richard Henderson
6180cc4027 target/mips: Don't use tcg_temp_local_new
Since tcg_temp_new is now identical, use that.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-03-01 07:33:28 -10:00
Richard Henderson
3a5d177322 target/i386: Don't use tcg_temp_local_new
Since tcg_temp_new is now identical, use that.
In some cases we can avoid a copy from A0 or T0.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-03-01 07:33:28 -10:00
Richard Henderson
e3eb3dab50 target/hppa: Don't use tcg_temp_local_new
This wasn't actually used at all, just some unused
macro re-definitions.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-03-01 07:33:28 -10:00
Richard Henderson
839a0ff284 target/hexagon/idef-parser: Drop gen_tmp_local
This is now equivalent to gen_tmp.

Reviewed-by: Taylor Simpson <tsimpson@quicinc.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-03-01 07:33:28 -10:00
Richard Henderson
7a819de850 target/hexagon: Don't use tcg_temp_local_new_*
Since tcg_temp_new_* is now identical, use those.

Reviewed-by: Taylor Simpson <tsimpson@quicinc.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-03-01 07:33:28 -10:00
Richard Henderson
5f153b12ab target/cris: Don't use tcg_temp_local_new
Since tcg_temp_new is now identical, use that.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-03-01 07:33:28 -10:00
Richard Henderson
d4aa49acd3 target/arm: Don't use tcg_temp_local_new_*
Since tcg_temp_new_* is now identical, use those.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-03-01 07:33:28 -10:00
Richard Henderson
78817d3b9f target/arm: Drop copies in gen_sve_{ldr,str}
Since we now get TEMP_TB temporaries by default, we no longer
need to make copies across these loops.  These were the only
uses of new_tmp_a64_local(), so remove that as well.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-03-01 07:33:28 -10:00
Richard Henderson
597f9b2d30 accel/tcg: Pass max_insn to gen_intermediate_code by pointer
In preparation for returning the number of insns generated
via the same pointer.  Adjust only the prototypes so far.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-03-01 07:33:27 -10:00
Anton Johansson
f51a1dd72f target/arm: Replace tb_pc() with tb->pc
Signed-off-by: Anton Johansson <anjo@rev.ng>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20230227135202.9710-27-anjo@rev.ng>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-03-01 07:33:25 -10:00
Anton Johansson
604b66ce5e target/avr: Replace tb_pc() with tb->pc
Signed-off-by: Anton Johansson <anjo@rev.ng>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20230227135202.9710-26-anjo@rev.ng>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-03-01 07:33:24 -10:00
Anton Johansson
ba44565588 target/hexagon: Replace tb_pc() with tb->pc
Signed-off-by: Anton Johansson <anjo@rev.ng>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Taylor Simpson <tsimpson@quicinc.com>
Message-Id: <20230227135202.9710-25-anjo@rev.ng>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-03-01 07:33:22 -10:00
Anton Johansson
2554f80f38 target/hppa: Replace tb_pc() with tb->pc
Signed-off-by: Anton Johansson <anjo@rev.ng>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20230227135202.9710-24-anjo@rev.ng>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-03-01 07:33:21 -10:00
Anton Johansson
34a39c2443 target/i386: Replace tb_pc() with tb->pc
Signed-off-by: Anton Johansson <anjo@rev.ng>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20230227135202.9710-23-anjo@rev.ng>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-03-01 07:33:20 -10:00
Anton Johansson
e83cf1c119 target/loongarch: Replace tb_pc() with tb->pc
Signed-off-by: Anton Johansson <anjo@rev.ng>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20230227135202.9710-22-anjo@rev.ng>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-03-01 07:33:19 -10:00
Anton Johansson
ca647d4564 target/microblaze: Replace tb_pc() with tb->pc
Signed-off-by: Anton Johansson <anjo@rev.ng>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20230227135202.9710-21-anjo@rev.ng>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-03-01 07:33:18 -10:00
Anton Johansson
420bf265be target/mips: Replace tb_pc() with tb->pc
Signed-off-by: Anton Johansson <anjo@rev.ng>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20230227135202.9710-20-anjo@rev.ng>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-03-01 07:33:17 -10:00
Anton Johansson
1aca4a2b31 target/openrisc: Replace tb_pc() with tb->pc
Signed-off-by: Anton Johansson <anjo@rev.ng>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20230227135202.9710-19-anjo@rev.ng>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-03-01 07:33:15 -10:00
Anton Johansson
0489d5bd06 target/riscv: Replace tb_pc() with tb->pc
Signed-off-by: Anton Johansson <anjo@rev.ng>
Reviewed-by: Palmer Dabbelt <palmer@rivosinc.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20230227135202.9710-18-anjo@rev.ng>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-03-01 07:33:14 -10:00
Anton Johansson
8023d1abcd target/rx: Replace tb_pc() with tb->pc
Signed-off-by: Anton Johansson <anjo@rev.ng>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20230227135202.9710-17-anjo@rev.ng>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-03-01 07:33:11 -10:00
Anton Johansson
dd69c77cc6 target/sh4: Replace tb_pc() with tb->pc
Signed-off-by: Anton Johansson <anjo@rev.ng>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20230227135202.9710-16-anjo@rev.ng>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-03-01 07:33:07 -10:00
Anton Johansson
c4bf3a9226 target/sparc: Replace tb_pc() with tb->pc
Signed-off-by: Anton Johansson <anjo@rev.ng>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20230227135202.9710-15-anjo@rev.ng>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-03-01 07:33:06 -10:00
Anton Johansson
25acb5e442 target/tricore: Replace tb_pc() with tb->pc
Signed-off-by: Anton Johansson <anjo@rev.ng>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20230227135202.9710-14-anjo@rev.ng>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-03-01 07:33:05 -10:00
Anton Johansson
f6680c5ea4 target/i386: Remove TARGET_TB_PCREL define
Signed-off-by: Anton Johansson <anjo@rev.ng>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20230227135202.9710-11-anjo@rev.ng>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-03-01 07:33:02 -10:00
Anton Johansson
48fbcf5c6c target/arm: Remove TARGET_TB_PCREL define
Signed-off-by: Anton Johansson <anjo@rev.ng>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20230227135202.9710-10-anjo@rev.ng>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-03-01 07:32:07 -10:00
Anton Johansson
2e3afe8e19 target/i386: Replace TARGET_TB_PCREL with CF_PCREL
Signed-off-by: Anton Johansson <anjo@rev.ng>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20230227135202.9710-8-anjo@rev.ng>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-03-01 07:31:56 -10:00
Anton Johansson
03a648c4b8 target/arm: Replace TARGET_TB_PCREL with CF_PCREL
Signed-off-by: Anton Johansson <anjo@rev.ng>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20230227135202.9710-7-anjo@rev.ng>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-03-01 07:31:52 -10:00
Anton Johansson
e607ea39ef target/arm: set CF_PCREL in arm_cpu_realizefn
Signed-off-by: Anton Johansson <anjo@rev.ng>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20230227135202.9710-4-anjo@rev.ng>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-03-01 07:31:33 -10:00
Anton Johansson
492f8b88ae target/i386: set CF_PCREL in x86_cpu_realizefn
Signed-off-by: Anton Johansson <anjo@rev.ng>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20230227135202.9710-3-anjo@rev.ng>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-03-01 07:31:27 -10:00
David Woodhouse
e16aff4cc2 kvm/i386: Add xen-evtchn-max-pirq property
The default number of PIRQs is set to 256 to avoid issues with 32-bit MSI
devices. Allow it to be increased if the user desires.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>
2023-03-01 09:09:22 +00:00
David Woodhouse
6096cf7877 hw/xen: Support MSI mapping to PIRQ
The way that Xen handles MSI PIRQs is kind of awful.

There is a special MSI message which targets a PIRQ. The vector in the
low bits of data must be zero. The low 8 bits of the PIRQ# are in the
destination ID field, the extended destination ID field is unused, and
instead the high bits of the PIRQ# are in the high 32 bits of the address.

Using the high bits of the address means that we can't intercept and
translate these messages in kvm_send_msi(), because they won't be caught
by the APIC — addresses like 0x1000fee46000 aren't in the APIC's range.

So we catch them in pci_msi_trigger() instead, and deliver the event
channel directly.

That isn't even the worst part. The worst part is that Xen snoops on
writes to devices' MSI vectors while they are *masked*. When a MSI
message is written which looks like it targets a PIRQ, it remembers
the device and vector for later.

When the guest makes a hypercall to bind that PIRQ# (snooped from a
marked MSI vector) to an event channel port, Xen *unmasks* that MSI
vector on the device. Xen guests using PIRQ delivery of MSI don't
ever actually unmask the MSI for themselves.

Now that this is working we can finally enable XENFEAT_hvm_pirqs and
let the guest use it all.

Tested with passthrough igb and emulated e1000e + AHCI.

           CPU0       CPU1
  0:         65          0   IO-APIC   2-edge      timer
  1:          0         14  xen-pirq   1-ioapic-edge  i8042
  4:          0        846  xen-pirq   4-ioapic-edge  ttyS0
  8:          1          0  xen-pirq   8-ioapic-edge  rtc0
  9:          0          0  xen-pirq   9-ioapic-level  acpi
 12:        257          0  xen-pirq  12-ioapic-edge  i8042
 24:       9600          0  xen-percpu    -virq      timer0
 25:       2758          0  xen-percpu    -ipi       resched0
 26:          0          0  xen-percpu    -ipi       callfunc0
 27:          0          0  xen-percpu    -virq      debug0
 28:       1526          0  xen-percpu    -ipi       callfuncsingle0
 29:          0          0  xen-percpu    -ipi       spinlock0
 30:          0       8608  xen-percpu    -virq      timer1
 31:          0        874  xen-percpu    -ipi       resched1
 32:          0          0  xen-percpu    -ipi       callfunc1
 33:          0          0  xen-percpu    -virq      debug1
 34:          0       1617  xen-percpu    -ipi       callfuncsingle1
 35:          0          0  xen-percpu    -ipi       spinlock1
 36:          8          0   xen-dyn    -event     xenbus
 37:          0       6046  xen-pirq    -msi       ahci[0000:00:03.0]
 38:          1          0  xen-pirq    -msi-x     ens4
 39:          0         73  xen-pirq    -msi-x     ens4-rx-0
 40:         14          0  xen-pirq    -msi-x     ens4-rx-1
 41:          0         32  xen-pirq    -msi-x     ens4-tx-0
 42:         47          0  xen-pirq    -msi-x     ens4-tx-1

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>
2023-03-01 09:09:22 +00:00
David Woodhouse
aa98ee38a5 hw/xen: Implement emulated PIRQ hypercall support
This wires up the basic infrastructure but the actual interrupts aren't
there yet, so don't advertise it to the guest.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>
2023-03-01 09:09:01 +00:00
David Woodhouse
799c23548f i386/xen: Implement HYPERVISOR_physdev_op
Just hook up the basic hypercalls to stubs in xen_evtchn.c for now.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>
2023-03-01 09:08:26 +00:00
David Woodhouse
c08f5d0e53 hw/xen: Add xen_xenstore device for xenstore emulation
Just the basic shell, with the event channel hookup. It only dumps the
buffer for now; a real ring implmentation will come in a subsequent patch.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>
2023-03-01 09:08:26 +00:00
Joao Martins
c6623cc3e7 i386/xen: handle HVMOP_get_param
Which is used to fetch xenstore PFN and port to be used
by the guest. This is preallocated by the toolstack when
guest will just read those and use it straight away.

Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>
2023-03-01 09:07:52 +00:00
David Woodhouse
8b57d5c523 i386/xen: Reserve Xen special pages for console, xenstore rings
Xen has eight frames at 0xfeff8000 for this; we only really need two for
now and KVM puts the identity map at 0xfeffc000, so limit ourselves to
four.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>
2023-03-01 09:07:52 +00:00
Joao Martins
b746a77926 i386/xen: handle PV timer hypercalls
Introduce support for one shot and periodic mode of Xen PV timers,
whereby timer interrupts come through a special virq event channel
with deadlines being set through:

1) set_timer_op hypercall (only oneshot)
2) vcpu_op hypercall for {set,stop}_{singleshot,periodic}_timer
hypercalls

Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>
2023-03-01 09:07:52 +00:00
David Woodhouse
b46f9745b1 hw/xen: Implement GNTTABOP_query_size
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>
2023-03-01 09:07:52 +00:00
David Woodhouse
28b7ae94a2 i386/xen: Implement HYPERVISOR_grant_table_op and GNTTABOP_[gs]et_verson
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>
2023-03-01 09:07:52 +00:00
David Woodhouse
a28b0fc034 hw/xen: Add xen_gnttab device for grant table emulation
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>
2023-03-01 09:07:52 +00:00
David Woodhouse
6f43f2ee49 kvm/i386: Add xen-gnttab-max-frames property
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>
2023-03-01 09:07:52 +00:00
David Woodhouse
2aff696b10 hw/xen: Support HVM_PARAM_CALLBACK_TYPE_PCI_INTX callback
The guest is permitted to specify an arbitrary domain/bus/device/function
and INTX pin from which the callback IRQ shall appear to have come.

In QEMU we can only easily do this for devices that actually exist, and
even that requires us "knowing" that it's a PCMachine in order to find
the PCI root bus — although that's OK really because it's always true.

We also don't get to get notified of INTX routing changes, because we
can't do that as a passive observer; if we try to register a notifier
it will overwrite any existing notifier callback on the device.

But in practice, guests using PCI_INTX will only ever use pin A on the
Xen platform device, and won't swizzle the INTX routing after they set
it up. So this is just fine.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>
2023-03-01 09:07:50 +00:00
David Woodhouse
ddf0fd9ae1 hw/xen: Support HVM_PARAM_CALLBACK_TYPE_GSI callback
The GSI callback (and later PCI_INTX) is a level triggered interrupt. It
is asserted when an event channel is delivered to vCPU0, and is supposed
to be cleared when the vcpu_info->evtchn_upcall_pending field for vCPU0
is cleared again.

Thankfully, Xen does *not* assert the GSI if the guest sets its own
evtchn_upcall_pending field; we only need to assert the GSI when we
have delivered an event for ourselves. So that's the easy part, kind of.

There's a slight complexity in that we need to hold the BQL before we
can call qemu_set_irq(), and we definitely can't do that while holding
our own port_lock (because we'll need to take that from the qemu-side
functions that the PV backend drivers will call). So if we end up
wanting to set the IRQ in a context where we *don't* already hold the
BQL, defer to a BH.

However, we *do* need to poll for the evtchn_upcall_pending flag being
cleared. In an ideal world we would poll that when the EOI happens on
the PIC/IOAPIC. That's how it works in the kernel with the VFIO eventfd
pairs — one is used to trigger the interrupt, and the other works in the
other direction to 'resample' on EOI, and trigger the first eventfd
again if the line is still active.

However, QEMU doesn't seem to do that. Even VFIO level interrupts seem
to be supported by temporarily unmapping the device's BARs from the
guest when an interrupt happens, then trapping *all* MMIO to the device
and sending the 'resample' event on *every* MMIO access until the IRQ
is cleared! Maybe in future we'll plumb the 'resample' concept through
QEMU's irq framework but for now we'll do what Xen itself does: just
check the flag on every vmexit if the upcall GSI is known to be
asserted.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>
2023-03-01 09:06:44 +00:00
David Woodhouse
a15b10978f hw/xen: Implement EVTCHNOP_reset
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>
2023-03-01 08:22:50 +00:00