Fix bugs and support axvisor to run 2 vms

Cargo.toml

@@ -25,7 +25,7 @@ bitflags = "2.2"
 bit_field = "0.10"
 crate_interface = "0.1"
 
-riscv = "0.14.0"
+riscv = { version = "0.14.0", features = ["s-mode"] }
 riscv-h = "0.1"
 
 riscv-decode = "0.2.3"

src/lib.rs

@@ -20,6 +20,7 @@ mod vcpu;
 pub use self::percpu::RISCVPerCpu;
 pub use self::vcpu::RISCVVCpu;
 pub use detect::detect_h_extension as has_hardware_support;
+pub use regs::GprIndex;
 
 /// Extension ID for hypercall, defined by ourselves.
 /// `0x48`, `0x56`, `0x43` is "HVC" in ASCII.
@@ -34,14 +35,14 @@ pub struct RISCVVCpuCreateConfig {
     pub hart_id: usize,
     /// The physical address of the device tree blob.
     /// Default to `0x9000_0000`.
-    pub dtb_addr: axaddrspace::GuestPhysAddr,
+    pub dtb_addr: usize,
 }
 
 impl Default for RISCVVCpuCreateConfig {
     fn default() -> Self {
         Self {
             hart_id: 0,
-            dtb_addr: axaddrspace::GuestPhysAddr::from_usize(0x9000_0000),
+            dtb_addr: 0x9000_0000,
         }
     }
 }

src/trap.rs

@@ -1,8 +1,67 @@
+use crate::regs::*;
 use core::mem::size_of;
-
 use memoffset::offset_of;
+use riscv::ExceptionNumber;
+use riscv::result::{Error, Result};
 
-use crate::regs::*;
+/// Exception
+#[derive(Copy, Clone, Debug, Eq, PartialEq)]
+#[repr(usize)]
+pub enum Exception {
+    InstructionMisaligned = 0,
+    InstructionFault = 1,
+    IllegalInstruction = 2,
+    Breakpoint = 3,
+    LoadMisaligned = 4,
+    LoadFault = 5,
+    StoreMisaligned = 6,
+    StoreFault = 7,
+    UserEnvCall = 8,
+    SupervisorEnvCall = 9,
+    VirtualSupervisorEnvCall = 10,
+    InstructionPageFault = 12,
+    LoadPageFault = 13,
+    StorePageFault = 15,
+    InstructionGuestPageFault = 20,
+    LoadGuestPageFault = 21,
+    VirtualInstruction = 22,
+    StoreGuestPageFault = 23,
+}
+
+/// SAFETY: `Exception` represents the standard RISC-V exceptions
+unsafe impl ExceptionNumber for Exception {
+    const MAX_EXCEPTION_NUMBER: usize = Self::StoreGuestPageFault as usize;
+
+    #[inline]
+    fn number(self) -> usize {
+        self as usize
+    }
+
+    #[inline]
+    fn from_number(value: usize) -> Result<Self> {
+        match value {
+            0 => Ok(Self::InstructionMisaligned),
+            1 => Ok(Self::InstructionFault),
+            2 => Ok(Self::IllegalInstruction),
+            3 => Ok(Self::Breakpoint),
+            4 => Ok(Self::LoadMisaligned),
+            5 => Ok(Self::LoadFault),
+            6 => Ok(Self::StoreMisaligned),
+            7 => Ok(Self::StoreFault),
+            8 => Ok(Self::UserEnvCall),
+            9 => Ok(Self::SupervisorEnvCall),
+            10 => Ok(Self::VirtualSupervisorEnvCall),
+            12 => Ok(Self::InstructionPageFault),
+            13 => Ok(Self::LoadPageFault),
+            15 => Ok(Self::StorePageFault),
+            20 => Ok(Self::InstructionGuestPageFault),
+            21 => Ok(Self::LoadGuestPageFault),
+            22 => Ok(Self::VirtualInstruction),
+            23 => Ok(Self::StoreGuestPageFault),
+            _ => Err(Error::InvalidVariant(value)),
+        }
+    }
+}
 
 #[allow(dead_code)]
 const fn hyp_gpr_offset(index: GprIndex) -> usize {

src/vcpu.rs

@@ -3,11 +3,23 @@ use riscv_decode::{
     Instruction,
     types::{IType, SType},
 };
-use riscv_h::register::{hstatus, hvip};
+use riscv_h::register::{
+    hstatus, htimedelta, hvip,
+    vsatp::{self, Vsatp},
+    vscause::{self, Vscause},
+    vsepc,
+    vsie::{self, Vsie},
+    vsscratch,
+    vsstatus::{self, Vsstatus},
+    vstval,
+    vstvec::{self, Vstvec},
+};
 use rustsbi::{Forward, RustSBI};
-use sbi_spec::{hsm, legacy};
+use sbi_spec::{hsm, legacy, srst};
 
-use crate::{EID_HVC, RISCVVCpuCreateConfig, guest_mem, regs::*, sbi_console::*};
+use crate::{
+    EID_HVC, RISCVVCpuCreateConfig, consts::traps::irq::S_EXT, guest_mem, regs::*, sbi_console::*,
+};
 
 use axaddrspace::{GuestPhysAddr, GuestVirtAddr, HostPhysAddr, MappingFlags, device::AccessWidth};
 use axerrno::{AxError::InvalidData, AxResult};
@@ -17,6 +29,14 @@ unsafe extern "C" {
     fn _run_guest(state: *mut VmCpuRegisters);
 }
 
+const TINST_PSEUDO_STORE: u32 = 0x3020;
+const TINST_PSEUDO_LOAD: u32 = 0x3000;
+
+#[inline]
+fn instr_is_pseudo(ins: u32) -> bool {
+    ins == TINST_PSEUDO_STORE || ins == TINST_PSEUDO_LOAD
+}
+
 /// The architecture dependent configuration of a `AxArchVCpu`.
 #[derive(Clone, Copy, Debug, Default)]
 pub struct VCpuConfig {}
@@ -53,9 +73,7 @@ impl<H: AxVCpuHal> axvcpu::AxArchVCpu for RISCVVCpu<H> {
         // `a0` is the hartid
         regs.guest_regs.gprs.set_reg(GprIndex::A0, config.hart_id);
         // `a1` is the address of the device tree blob.
-        regs.guest_regs
-            .gprs
-            .set_reg(GprIndex::A1, config.dtb_addr.as_usize());
+        regs.guest_regs.gprs.set_reg(GprIndex::A1, config.dtb_addr);
 
         Ok(Self {
             regs,
@@ -67,12 +85,15 @@ impl<H: AxVCpuHal> axvcpu::AxArchVCpu for RISCVVCpu<H> {
     fn setup(&mut self, _config: Self::SetupConfig) -> AxResult {
         // Set sstatus.
         let mut sstatus = sstatus::read();
+        sstatus.set_sie(false);
+        sstatus.set_spie(false);
         sstatus.set_spp(sstatus::SPP::Supervisor);
         self.regs.guest_regs.sstatus = sstatus.bits();
 
         // Set hstatus.
         let mut hstatus = hstatus::read();
         hstatus.set_spv(true);
+        hstatus.set_vsxl(hstatus::VsxlValues::Vsxl64);
         // Set SPVP bit in order to accessing VS-mode memory from HS-mode.
         hstatus.set_spvp(true);
         unsafe {
@@ -114,7 +135,26 @@ impl<H: AxVCpuHal> axvcpu::AxArchVCpu for RISCVVCpu<H> {
     }
 
     fn bind(&mut self) -> AxResult {
+        // Load the vCPU's CSRs from the stored state.
         unsafe {
+            let vsatp = Vsatp::from_bits(self.regs.vs_csrs.vsatp);
+            vsatp.write();
+            let vstvec = Vstvec::from_bits(self.regs.vs_csrs.vstvec);
+            vstvec.write();
+            let vsepc = self.regs.vs_csrs.vsepc;
+            vsepc::write(vsepc);
+            let vstval = self.regs.vs_csrs.vstval;
+            vstval::write(vstval);
+            let htimedelta = self.regs.vs_csrs.htimedelta;
+            htimedelta::write(htimedelta);
+            let vscause = Vscause::from_bits(self.regs.vs_csrs.vscause);
+            vscause.write();
+            let vsscratch = self.regs.vs_csrs.vsscratch;
+            vsscratch::write(vsscratch);
+            let vsstatus = Vsstatus::from_bits(self.regs.vs_csrs.vsstatus);
+            vsstatus.write();
+            let vsie = Vsie::from_bits(self.regs.vs_csrs.vsie);
+            vsie.write();
             core::arch::asm!(
                 "csrw hgatp, {hgatp}",
                 hgatp = in(reg) self.regs.virtual_hs_csrs.hgatp,
@@ -125,14 +165,35 @@ impl<H: AxVCpuHal> axvcpu::AxArchVCpu for RISCVVCpu<H> {
     }
 
     fn unbind(&mut self) -> AxResult {
+        // Store the vCPU's CSRs to the stored state.
+        unsafe {
+            self.regs.vs_csrs.vsatp = vsatp::read().bits();
+            self.regs.vs_csrs.vstvec = vstvec::read().bits();
+            self.regs.vs_csrs.vsepc = vsepc::read();
+            self.regs.vs_csrs.vstval = vstval::read();
+            self.regs.vs_csrs.htimedelta = htimedelta::read();
+            self.regs.vs_csrs.vscause = vscause::read().bits();
+            self.regs.vs_csrs.vsscratch = vsscratch::read();
+            self.regs.vs_csrs.vsstatus = vsstatus::read().bits();
+            self.regs.vs_csrs.vsie = vsie::read().bits();
+            core::arch::asm!(
+                "csrr {hgatp}, hgatp",
+                hgatp = out(reg) self.regs.virtual_hs_csrs.hgatp,
+            );
+            core::arch::asm!("csrw hgatp, x0");
+            core::arch::riscv64::hfence_gvma_all();
+        }
         Ok(())
     }
 
     /// Set one of the vCPU's general purpose register.
     fn set_gpr(&mut self, index: usize, val: usize) {
         match index {
-            0..=7 => {
-                self.set_gpr_from_gpr_index(GprIndex::from_raw(index as u32 + 10).unwrap(), val);
+            0 => {
+                // Do nothing, x0 is hardwired to zero
+            }
+            1..=31 => {
+                self.set_gpr_from_gpr_index(GprIndex::from_raw(index as u32).unwrap(), val);
             }
             _ => {
                 warn!(
@@ -179,7 +240,8 @@ impl<H: AxVCpuHal> RISCVVCpu<H> {
         self.regs.trap_csrs.load_from_hw();
 
         let scause = scause::read();
-        use riscv::interrupt::{Exception, Interrupt, Trap};
+        use super::trap::Exception;
+        use riscv::interrupt::{Interrupt, Trap};
 
         trace!(
             "vmexit_handler: {:?}, sepc: {:#x}, stval: {:#x}",
@@ -189,13 +251,13 @@ impl<H: AxVCpuHal> RISCVVCpu<H> {
         );
 
         // Try to convert the raw trap cause to a standard RISC-V trap cause.
-        let trap = scause.cause().try_into().map_err(|_| {
+        let trap: Trap<Interrupt, Exception> = scause.cause().try_into().map_err(|_| {
             error!("Unknown trap cause: scause={:#x}", scause.bits());
             InvalidData
         })?;
 
         match trap {
-            Trap::Exception(Exception::SupervisorEnvCall) => {
+            Trap::Exception(Exception::VirtualSupervisorEnvCall) => {
                 let a = self.regs.guest_regs.gprs.a_regs();
                 let param = [a[0], a[1], a[2], a[3], a[4], a[5]];
                 let extension_id = a[7];
@@ -348,6 +410,21 @@ impl<H: AxVCpuHal> RISCVVCpu<H> {
                             return Ok(AxVCpuExitReason::Nothing);
                         }
                     },
+                    srst::EID_SRST => match function_id {
+                        srst::SYSTEM_RESET => {
+                            let reset_type = param[0];
+                            if reset_type == srst::RESET_TYPE_SHUTDOWN as _ {
+                                // Shutdown the system.
+                                return Ok(AxVCpuExitReason::SystemDown);
+                            } else {
+                                unimplemented!("Unsupported reset type {}", reset_type);
+                            }
+                        }
+                        _ => {
+                            self.sbi_return(RET_ERR_NOT_SUPPORTED, 0);
+                            return Ok(AxVCpuExitReason::Nothing);
+                        }
+                    },
                     // By default, forward the SBI call to the RustSBI implementation.
                     // See [`RISCVVCpuSbi`].
                     _ => {
@@ -381,11 +458,11 @@ impl<H: AxVCpuHal> RISCVVCpu<H> {
                 // It's a great fault in the `riscv` crate that `Interrupt` and `Exception` are not
                 // explicitly numbered, and they provide no way to convert them to a number. Also,
                 // `as usize` will give use a wrong value.
-                Ok(AxVCpuExitReason::ExternalInterrupt { vector: 9 })
-            }
-            Trap::Exception(gpf @ (Exception::LoadPageFault | Exception::StorePageFault)) => {
-                self.handle_guest_page_fault(gpf == Exception::StorePageFault)
+                Ok(AxVCpuExitReason::ExternalInterrupt { vector: S_EXT as _ })
             }
+            Trap::Exception(
+                gpf @ (Exception::LoadGuestPageFault | Exception::StoreGuestPageFault),
+            ) => self.handle_guest_page_fault(gpf == Exception::StoreGuestPageFault),
             _ => {
                 panic!(
                     "Unhandled trap: {:?}, sepc: {:#x}, stval: {:#x}",
@@ -409,13 +486,35 @@ impl<H: AxVCpuHal> RISCVVCpu<H> {
     fn decode_instr_at(&self, vaddr: GuestVirtAddr) -> AxResult<(Instruction, usize)> {
         // The htinst CSR contains "transformed instruction" that caused the page fault. We
         // can use it but we use the sepc to fetch the original instruction instead for now.
-        let instr = guest_mem::fetch_guest_instruction(vaddr);
-        let instr_len = riscv_decode::instruction_length(instr as u16);
-        let instr = match instr_len {
-            2 => instr & 0xffff,
-            4 => instr,
-            _ => unreachable!("Unsupported instruction length: {}", instr_len),
-        };
+        let mut instr = riscv_h::register::htinst::read();
+        let mut instr_len = 0;
+        if instr == 0 {
+            // Read the instruction from guest memory.
+            instr = guest_mem::fetch_guest_instruction(vaddr) as _;
+            instr_len = riscv_decode::instruction_length(instr as u16);
+            instr = match instr_len {
+                2 => instr & 0xffff,
+                4 => instr,
+                _ => unreachable!("Unsupported instruction length: {}", instr_len),
+            };
+        } else if instr_is_pseudo(instr as u32) {
+            error!("fault on 1st stage page table walk");
+            return Err(axerrno::ax_err_type!(
+                Unsupported,
+                "risc-v vcpu guest page fault handler encountered pseudo instruction"
+            ));
+        } else {
+            // Transform htinst value to standard instruction.
+            // According to RISC-V Spec:
+            //      Bits 1:0 of a transformed standard instruction will be binary 01 if
+            //      the trapping instruction is compressed and 11 if not.
+            instr_len = match (instr as u16) & 0x3 {
+                0x1 => 2,
+                0x3 => 4,
+                _ => unreachable!("Unsupported instruction length"),
+            };
+            instr |= 0x2;
+        }
 
         riscv_decode::decode(instr as u32)
             .map_err(|_| {